delivered the opinion of the Court.
This is an action brought by respondent under Rev. Stat. § 1979, 42 U. S. C. § 1983, against state law enforcement officers who conducted a warrantless search of his house incident to his arrest for the sale of methamphetamine to an undercover informant whom he had voluntarily admitted to the premises. The Court of Appeals held that petitioners were not entitled to summary judgment on qualified immunity grounds. Following the procedure we mandated in
Saucier
v.
Katz,
We now hold that the Saucier procedure should not be regarded as an inflexible requirement and that petitioners are entitled to qualified immunity on the ground that it was not clearly established at the time of the search that their conduct was unconstitutional. We therefore reverse.
I
A
The Central Utah Narcotics Task Force is charged with investigating illegal drug use and sales. In 2002, Brian Bartholomew, who became an informant for the task force after having been charged with the unlawful possession of methamphetamine, informed Officer Jeffrey Whatcott that respondent Afton Callahan had arranged to sell Bartholomew methamphetamine later that day.
That evening, Bartholomew arrived at respondent’s residence at about 8 p.m. Once there, Bartholomew went inside and confirmed that respondent had methamphetamine available for sale. Bartholomew then told respondent that he needed to obtain money to make his purchase and left.
*228 Bartholomew met with members of the task force at about 9 p.m. and told them that he would be able to buy a gram of methamphetamine for $100. After concluding that Bartholomew was capable of completing the planned purchase, the officers searched him, determined that he had no controlled substances on his person, gave him a marked $100 bill and a concealed electronic transmitter to monitor his conversations, and agreed on a signal that he would give after completing the purchase.
The officers drove Bartholomew to respondent’s trailer home, and respondent’s daughter let him inside. Respondent then retrieved a large bag containing methamphetamine from his freezer and sold Bartholomew a gram of methamphetamine, which he put into a small plastic bag. Bartholomew gave the arrest signal to the officers who were monitoring the conversation, and they entered the trailer through a porch door. In the enclosed porch, the officers encountered Bartholomew, respondent, and two other persons, and they saw respondent drop a plastic bag, which they later determined contained methamphetamine. The officers then conducted a protective sweep of the premises. In addition to the large bag of methamphetamine, the officers recovered the marked bill from respondent and a small bag containing methamphetamine from Bartholomew, and they found drug syringes in the residence. As a result, respondent was charged with the unlawful possession and distribution of methamphetamine.
B
The trial court held that the warrantless arrest and search were supported by exigent circumstances. On respondent’s appeal from his conviction, the Utah attorney general conceded the absence of exigent circumstances, but urged that the inevitable discovery doctrine justified introduction of the fruits of the warrantless search. The Utah Court of Appeals disagreed and vacated respondent’s conviction. See
State
v.
Callahan,
In granting the officers’ motion for summary judgment, the District Court noted that other courts had adopted the “consent-once-removed” doctrine, which permits a warrant-less entry by police officers into a home when consent to enter has already been granted to an undercover officer or informant who has observed contraband in plain view. Believing that this doctrine was in tension with our intervening decision in
Georgia
v.
Randolph,
On appeal, a divided panel of the Tenth Circuit held that petitioners’ conduct violated respondent’s Fourth Amendment rights.
Callahan
v.
Millard Cty.,
*230 The Tenth Circuit panel further held that the Fourth Amendment right that it recognized was clearly established at the time of respondent’s arrest. Id., at 898-899. “In this case,” the majority stated, “the relevant right is the right to be free in one’s home from unreasonable searches and arrests.” Id., at 898. The Court determined that, under the clearly established precedents of this Court and the Tenth Circuit, “warrantless entries into a home are per se unreasonable unless they satisfy the established exceptions.” Id., at 898-899. In the panel’s words, “the Supreme Court and the Tenth Circuit have clearly established that to allow police entry into a home, the only two exceptions to the warrant requirement are consent and exigent circumstances.” Id., at 899. Against that backdrop, the panel concluded, petitioners could not reasonably have believed that their conduct was lawful because petitioners “knew (1) they had no warrant; (2) [respondent] had not consented to their entry; and (3) [respondent’s] consent to the entry of an informant could not reasonably be interpreted to extend to them.” Ibid.
In dissent, Judge Kelly argued that “no constitutional violation occurred in this case” because, by inviting Bartholomew into his house and participating in a narcotics transaction there, respondent had compromised the privacy of the residence and had assumed the risk that Bartholomew would reveal their dealings to the police. Id., at 903. Judge Kelly further concluded that, even if petitioners’ conduct had been unlawful, they were nevertheless entitled to qualified immunity because the constitutional right at issue — “the right to be free from the warrantless entry of police officers into one’s home to effectuate an arrest after one has granted voluntary, consensual entry to a confidential informant and undertaken criminal activity giving rise to probable cause” — was not “clearly established” at the time of the events in question. Id., at 903-904.
*231
As noted, the Court of Appeals followed the
Saucier
procedure. The
Saucier
procedure has been criticized by Members of this Court and by lower court judges, who have been required to apply the procedure in a great variety of cases and thus have much firsthand experience bearing on its advantages and disadvantages. Accordingly, in granting certiorari, we directed the parties to address the question whether
Saucier
should be overruled.
II
A
The doctrine of qualified immunity protects government officials “from liability for civil damages insofar as their conduct does not violate clearly established statutory or constitutional rights of which a reasonable person would have known.”
Harlow
v.
Fitzgerald,
Because qualified immunity is “an immunity from suit rather than a mere defense to liability... it is effectively lost if a case is erroneously permitted to go to trial.”
Mitchell
v.
Forsyth,
In
Saucier,
Our decisions prior to
Saucier
had held that “the better approach to resolving cases in which the defense of qualified immunity is raised is to determine first whether the plaintiff has alleged a deprivation of a constitutional right at all.”
County of Sacramento
v.
Lewis,
This two-step procedure, the Saucier Court reasoned, is necessary to support the Constitution’s “elaboration from case to case” and to prevent constitutional stagnation. Ibid. “The law might be deprived of this explanation were a court simply to skip ahead'to the question whether the law clearly established that the officer’s conduct was unlawful in the circumstances of the case.” Ibid.
*233 B
In considering whether the
Saucier
procedure should be modified or abandoned, we must begin with the doctrine of
stare decisis. Stare decisis
“promotes the evenhanded, predictable, and consistent development of legal principles, fosters reliance on judicial decisions, and contributes to the actual and perceived integrity of the judicial process.”
Payne
v.
Tennessee,
“Considerations in favor of
stare decisis
are at their acme in cases involving property and contract rights, where reliance interests are involved; the opposite is true in cases .. . involving procedural and evidentiary rules” that do not produce such reliance.
Payne, supra,
at 828 (citations omitted). Like rules governing procedures and the admission of evidence in the trial courts,
Saucier’s
two-step protocol does not affect the way in which parties order their affairs. Withdrawing from
Saucier’s
categorical rule would not upset settled expectations on anyone’s part. See
United States
v.
Gaudin,
Nor does this matter implicate “the general presumption that legislative changes should be left to Congress.”
Khan, supra,
at 20. We recognize that “considerations of
stare decisis
weigh heavily in the area of statutory construction, where Congress is free to change this Court’s interpretation of its legislation.”
Illinois Brick Co.
v.
Illinois,
Respondent argues that the .Saucier procedure should not be reconsidered unless we conclude that its justification was “badly reasoned” or that the rule has proved to be “unworkable,” see Payne, supra, at 827, but those standards, which are appropriate when a constitutional or statutory precedent is challenged, are out of place in the present context. Because of the basis and the nature of the Saucier two-step protocol, it is sufficient that we now have a considerable body of new experience to consider regarding the consequences of requiring adherence to this inflexible procedure. This experience supports our present determination that a mandatory, two-step rule for resolving all qualified immunity claims should not be retained.
Lower court judges, who have had the task of applying the
Saucier
rule on a regular basis for the past eight years, have not been reticent in their criticism of
Saucier’s
“rigid order of battle.” See,
e. g., Purtell
v.
Mason,
Members of this Court have also voiced criticism of the
Saucier
rule. See
Morse
v.
Frederick,
Where a decision has “been questioned by Members of the Court in later decisions and [has] defied consistent application by the lower courts,” these factors weigh in favor of reconsideration.
Payne,
*236 III
On reconsidering the procedure required in Saucier, we conclude that, while the sequence set forth there is often appropriate, it should no longer be regarded as mandatory. The judges of the district courts and the courts of appeals should be permitted to exercise their sound discretion in deciding which of the two prongs of the qualified immunity analysis should be addressed first in light of the circumstances in the particular case at hand.
A
Although we now hold that the
Saucier
protocol should not be regarded as mandatory in all cases, we continue to recognize that it is often beneficial. For one thing, there aré cases in which there would be little if any conservation of judicial resources to be had by beginning and ending with a discussion of the “clearly established” prong. “[I]t often may be difficult to decide whether a right is clearly established without deciding precisely what the existing constitutional right happens to be.”
Lyons
v.
Xenia,
B
At the same time, however, the rigid Saucier procedure comes with a price. The procedure sometimes results in a substantial expenditure of scarce judicial resources on diffi *237 cult questions that have no effect on the outcome of the case. There are cases in which it is plain that a constitutional right is not clearly established but far from obvious whether in fact there is such a right. District courts and courts of appeals with heavy caseloads are often understandably unenthusiastic about what may seem to be an essentially academic exercise.
Unnecessary litigation of constitutional issues also wastes the parties’ resources. Qualified immunity is “an immunity from suit rather than a mere defense to liability.”
Mitchell,
Although the first prong of the
Saucier
procedure is intended to further the development of constitutional precedent, opinions following that procedure often fail to make a meaningful contribution to such development. For one thing, there are cases in which the constitutional question is so factbound that the decision provides little guidance for future cases. See
Scott
v.
Harris,
A decision on the underlying constitutional question in a § 1983 damages action or a
Bivens
v.
Six Unknown Fed. Nar
*238
cotics Agents,
A constitutional decision resting on an uncertain interpretation of state law is also of doubtful precedential importance. As a result, several courts have identified an “exception” to the
Saucier
rule for cases in which resolution of the constitutional question requires clarification of an ambiguous state statute.
Egolf v. Witmer,
When qualified immunity is asserted at the pleading stage, the precise factual basis for the plaintiff’s claim or claims
*239
may be hard to identify. See
Lyons,
There are circumstances in which the first step of the Saucier procedure may create a risk of bad decisionmaking. The lower courts sometimes encounter cases in which the briefing of constitutional questions is woefully inadequate. See Lyons, supra, at 582 (Sutton, J., concurring) (noting the “risk that constitutional questions may be prematurely and incorrectly decided in.cases where they are not well presented”); Mollica, supra, at 374.
Although the
Saucier
rule prescribes the sequence in which the issues must be discussed by a court in its opinion, the rule does not — and obviously cannot — specify the sequence in which judges reach their conclusions in their own internal thought processes. Thus, there will be cases in which a court will rather quickly and easily decide that there was no violation of clearly established law before turning to the more difficult question whether the relevant facts make out a constitutional question at all. In such situations, there is a risk that a court may not devote as much care as it would in other circumstances to the decision of the constitutional issue. See
Horne
v.
Coughlin,
Rigid adherence to the
Saucier
rule may make it hard for affected parties to obtain appellate review of constitutional decisions that may have a serious prospective effect on their operations. Where a court holds that a defendant committed a constitutional violation but that the violation was not clearly established, the defendant may face a difficult situation. As the winning party, the defendant’s right to appeal the adverse holding on the constitutional question may be contested. See
Bunting,
Adherence to
Saucier’s
two-step protocol departs from the general rule of constitutional avoidance and runs counter to the “older, wiser judicial counsel ‘not to pass on questions of constitutionality . . . unless such adjudication is unavoidable.’ ”
Scott,
In other analogous contexts, we have appropriately declined to mandate the order of decision that the lower courts must follow. For example, in
Strickland
v.
Washington,
In
United States
v.
Leon,
This flexibility properly reflects our respect for the lower federal courts that bear the brunt of adjudicating these cases. Because the two-step Saucier procedure is often, but not always, advantageous, the judges of the district courts and the courts of appeals are in the best position to determine the order of decisionmaking that will best facilitate the fair and efficient disposition of each case.
C
Any misgivings concerning our decision to withdraw from the mandate set forth in
Saucier
are unwarranted. Our decision does not prevent the lower courts from following the
Saucier
procedure; it simply recognizes that those courts should have the discretion to decide whether that procedure is worthwhile in particular cases. Moreover, the development of constitutional law is by no means entirely dependent on cases in which the defendant may seek qualified immunity. Most of the constitutional issues that are presented in § 1983 damages actions and
Bivens
cases also arise in cases in which that defense is not available, such as criminal cases and §1983 eases against a municipality, as well as §1983 cases against individuals where injunctive relief is sought instead of or in addition to damages. See
Lewis,
We also do not think that relaxation of Saucier’s mandate is likely to result in a proliferation of damages claims against local governments. Cf. Brief for National Association of Counties et al. as Amici Curiae 29, 30 (“[T]o the extent that a rule permitting courts to bypass the merits makes it more difficult for civil rights plaintiffs to pursue novel claims, they will have greater reason to press custom, policy, or practice [damages] claims against local governments”). It is hard to see how the Saucier procedure could have a significant effect on a civil rights plaintiff's decision whether to seek damages only from a municipal employee or also from the municipality. Whether the Saucier procedure is mandatory or discretionary, the plaintiff will presumably take into account the possibility that the individual defendant will be held to have qualified immunity, and presumably the plaintiff will seek damages from the municipality as well as the individual employee if the benefits of doing so (any increase in the likelihood of recovery or collection of damages) outweigh the litigation costs.
Nor do we think that allowing the lower courts to exercise their discretion with respect to the Saucier procedure will spawn “a new cottage industry of litigation . . . over the standards for deciding whether to reach the merits in a given case.” Brief for National Association of Counties, supra, at 29, 30. It does not appear that such a “cottage industry” developed prior to Saucier, and we see no reason why our decision today should produce such a result.
IV
Turning to the conduct of the officers here, we hold that petitioners are entitled to qualified immunity because the entry did not violate clearly established law. An officer conducting a search is entitled to qualified immunity where clearly established law does not show that the search vio
*244
lated the Fourth Amendment. See
Anderson,
When the entry at issue here occurred in 2002, the “consent-once-removed” doctrine had gained acceptance in the lower courts. This doctrine had been considered by three Federal Courts of Appeals and two State Supreme Courts starting in the early 1980’s. See,
e. g., United States
v.
Diaz,
The officers here were entitled to rely on these cases, even though their own Federal Circuit had not yet ruled on “consent-once-removed” entries. The principles of qualified immunity shield an officer from personal liability when an officer reasonably believes that his or her conduct complies with the law. Police officers are entitled to rely on existing lower court cases without facing personal liability for their
*245
actions. In
Wilson,
we explained that a Circuit split on the relevant issue had developed after the events that gave rise to suit and concluded that “[i]f judges thus disagree on a constitutional question, it is unfair to subject police to money damages for picking the losing side of the controversy.”
Because the unlawfulness of the officers’ conduct in this case was not clearly established, petitioners are entitled to qualified immunity. We therefore reverse the judgment of the Court of Appeals.
It is so ordered.
Notes
See
Harlow
v.
Fitzgerald,
In
Bunting,
the Court of Appeals followed the
Saucier
two-step protocol and first held that the Virginia Military Institute’s use of the word “God” in a “supper roll call” ceremony violated the Establishment Clause, but then granted the defendants qualified immunity because the law was not clearly established at the relevant time.
Mellen
v.
Bunting, 327
F. 3d 355, 365-376 (CA4 2003), cert. denied,