State v. Rourke, 154 A.3d 127

Early-morning traffic stop after speeding; officer smelled alcohol and observed signs of impairment; Rourke arrested for OUI.
Breath test on an Intoxilyzer 8000 produced a result of 0.11 g/210 L after an initial radio-frequency error and restart.
Rourke proffered expert Patrick Demers (pharmacy/forensic chemistry) to testify that inhalation exposure to hydrocarbons/ketones/toluene can falsely elevate Intoxilyzer readings.
Demers’s supporting experiments were decades old, used earlier Intoxilyzer models (4011, 5000), and relied in part on anecdotal/unidentified literature; he lacked experience with the Intoxilyzer 8000.
The trial court excluded Demers’s opinion under M.R. Evid. 403/702 for lack of reliability and insufficient foundation tying the opinion to Rourke’s specific exposure; jury convicted and court sentenced; judgment affirmed on appeal.

Issue	Rourke's Argument	State's Argument	Held
Admissibility of expert testimony that hydrocarbons could falsely elevate breath test	Demers should be allowed to testify that hydrocarbons/solvents can cause false positives and thus undermine the Intoxilyzer result	Testimony is unreliable and speculative: experiments not on Intoxilyzer 8000 and no proof Rourke was exposed at a relevant level	Excluded: court did not abuse discretion — testimony unreliable and not sufficiently linked to Rourke (M.R. Evid. 702, 403)
Whether exclusion violated Sixth Amendment compulsory process right	Exclusion prevented presentation of defense evidence	Expert testimony was inadmissible under evidentiary rules and not constitutionally required	No Sixth Amendment violation where testimony was inadmissible under standard evidence rules
Cumulative/prejudicial nature of overlapping officer testimony (preserved argument)	Overlapping field-sobriety testimony was unfairly prejudicial/cumulative	Testimony admissible; no undue prejudice	Appellate court unpersuaded; did not further address the contention

State v. Fay, 130 A.3d 364 (Maine 2015) (standard for viewing evidence in the light most favorable to the State)
State v. Ericson, 13 A.3d 777 (Me. 2011) (requirements for admissibility and reliability of expert testimony under Rule 702)
State v. Diana, 89 A.3d 132 (Me. 2014) (abuse-of-discretion review of expert-admissibility rulings)
State v. Hatt, 810 A.2d 415 (Me. 2002) (expert excluded where offer of proof insufficient to show relevance/link to defendant)
State v. Collin, 441 A.2d 693 (Me. 1982) (expert excluded when no record evidence links testimony to defendant)
State v. Boutilier, 426 A.2d 876 (Me. 1981) (unreliable expert testimony lacks probative value and may be excluded under Rules 402, 403, 702)
State v. Tellier, 526 A.2d 941 (Me. 1987) (expert testimony too speculative may be excluded)
State v. Cross, 732 A.2d 278 (Me. 1999) (Sixth Amendment does not guarantee right to present incompetent or inadmissible testimony)
Taylor v. Illinois, 484 U.S. 400 (U.S. 1988) (defendant’s compulsory process right limited by evidentiary rules)