Opinion for the Court filed PER CURIAM.
Seventeen plaintiffs brought suit to prevent the District of Columbia from acquiring a shopping center by eminent domain. *1300 Because only four of the plaintiffs own or lease properties in the shopping center, and those four are litigating this matter in the District of Columbia’s court system, we affirm the district court’s dismissal of the case.
The Skyland Shopping Center is located at the junction of Alabama Avenue, Good Hope Road, and Naylor Road in Southeast Washington, D.C. According to findings of the District of Columbia Council, the shopping center is in disrepair, is underutilized, contributes to crime, is an eyesore, presents traffic hazards, does not provide quality shopping, and is a “blighting factor” in the neighborhood. See National Capital Revitalization Corporation Eminent Domain Clarification and Skyland Eminent Domain Approval Amendment Act, D.C. Law 15-286, 52 D.C.Reg. 859 (2004) (the “Skyland Act”). In 2004, the Council authorized the National Capital Revitalization Corporation — a District agency — to acquire the properties comprising the shopping center by purchase or eminent domain. The District planned to transfer the land to a private company that would redevelop the area into a better shopping center with the attendant public benefits of increased revenue, jobs, and high quality shopping.
Plaintiffs are current and former Sky-land property owners, tenants, and employees who oppose the District’s plan. They brought suit in federal court shortly after the Council passed the Skyland Act, alleging that the proposed takings were intended to benefit the private developer rather than the public and thus violated the Takings Clause of the Fifth Amendment. They sought a judgment declaring the Act unconstitutional and enjoining the District from exercising eminent domain to acquire the shopping center. They also requested damages. After the district court denied plaintiffs’ motion for a preliminary injunction, the District initiated a series of condemnation proceedings in the District of Columbia Superior Court against Skyland parcels. One of these proceedings was brought against property owned by plaintiff Duk Hea Oh; another was brought against property owned by plaintiff Peter DeSilva and leased by plaintiffs Joseph and Rose Rumber. In light of these proceedings, the district court dismissed the claims of Oh, DeSilva, and the Rumbers under the principle of abstention articulated in
Younger v. Harris,
All seventeen plaintiffs now appeal, but thirteen plaintiffs’ claims are barred by the doctrines of mootness or standing. Four plaintiffs (Graham Fields, Verna Fields, Ingak Lee, and In Suk Baik) sold their property to the District and three others (Marion Fletcher, Hartej Singh, and Muneer Choudhury) are former leaseholders whose leases expired or terminated without being condemned. These plaintiffs have “nothing to gain” from an injunction against the use of eminent domain or a judgment declaring the Skyland Act unconstitutional; their claims are therefore moot.
See Taylor v. Resolution Trust Corp.,
Three other plaintiffs lack standing because they do not hold property interests in the shopping center. Plaintiffs Ling Chen and Boubaker Ben Salah are or were employees of businesses operating at the shopping center, and plaintiff Mukhtar Ahmadi holds an unspecified ownership stake in a business that leases a store at the shopping center. A plaintiff must ordinarily “assert his own legal interests, rather than those of third parties.”
Gladstone, Realtors v. Village of Bellwood,
That brings us to the district court’s decision to abstain under
Younger
with respect to the claims of the four condemnees. The
Younger
principle, as it has been shaped by a series of Supreme Court precedents, is that a federal court should not enjoin or declare illegal a pending state proceeding that is judicial in nature and involves important state interests,
JMM Corp. v. District of Columbia,
The condemnees claim that the Superior Court deprived them of a fair litiga
*1302
tion opportunity by ruling — in both condemnation actions — that the condemnees forfeited their constitutional defenses by failing to plead them. The condemnees did not provide, either to this court or the district court, copies of the relevant Superior Court pleadings or the forfeiture rulings. Nor did their briefs explain the rulings in any detail, leaving us unable to evaluate their fairness. But it does not matter anyway, because, as these plaintiffs acknowledge, the District of Columbia Court of Appeals shortly thereafter issued an opinion in a similarly-situated Skyland condemnation case that overturned those forfeiture rulings.
See Franco v. Nat’l Capital Revitalization Corp.,
As to “bad faith,” the Rumbers complain that the District did not join them as defendants in the DeSilva condemnation action for approximately two years after the District filed the condemnation complaint. This was bad faith, according to the Rumbers, because Superior Court rules require immediate joinder of all parties known to hold property interests. See Super. Ct. Civ. R. 71A(c)(2). The Rumbers accuse the District of knowing of their leasehold interest at the time of the initiation of the condemnation suit and deliberately delaying joining them as defendants. We cannot help but wonder what possible advantage the District hoped to gain through this strategy, or how the delay has prejudiced the Rumbers. The Rumbers were obviously on notice of the condemnation action because they have been suing to enjoin it since it began. We therefore agree with the district court that there was no bad faith.
Though we imagine that plaintiffs could have raised other arguments against abstention,
3
we follow our usual practice of declining to reverse the district court based on arguments that the appellant did not raise.
See Doe v. District of Columbia,
Affirmed.
Notes
. These plaintiffs argue that the complaint also includes claims for compensatory dam
*1301
ages, which are not capable of being moot.
See People for the Ethical Treatment of Animals, Inc. v. Gittens,
. In supplemental briefing, the District provided us with these license agreements. Each agreement contains a clause releasing the District "from and against any and all actions, causes of action, suits, debts, contracts, claims and/or demands pertaining to or arising from Licensee's occupancy of the Premises prior to the date hereto.” Plaintiff Baik also signed a similar license agreement, with an identical release clause, after selling his property to the District.
. For example, plaintiffs never argued that abstention was unwarranted with respect to the Rumbers because "proceedings of substance on the merits ha[d] taken place in the federal court” before the District joined the Rumbers in the DeSilva condemnation suit.
See Hawaii Housing Authority v. Midkiff,
