Seventh Circuit Clarifies Joint-Enterprise Contributory Negligence in Criminal Ventures and Narrows Illinois Dead-Man’s Act in Mixed Federal / State Actions

Introduction

In Michael Cokes v. City of Chicago, the United States Court of Appeals for the Seventh Circuit addressed a tragic high-speed police chase that ended with two deaths and multiple injuries. Plaintiffs—survivors and the estate of a deceased passenger—sued the City of Chicago and Officer Dean Ewing for excessive force and several state torts. A jury ruled for the defendants; the district court denied post-trial motions, and the plaintiffs appealed. The Seventh Circuit (Judges Easterbrook, Jackson-Akiwumi, and Kolar, opinion by Jackson-Akiwumi) affirmed, creating two significant precedential clarifications:

Illinois’ “joint enterprise” doctrine of contributory negligence can be pleaded in federal court even when the alleged enterprise is criminal.
In mixed federal/state cases, Federal Rule of Evidence 601—not the Illinois Dead-Man’s Act—governs witness competency whenever the testimony relates to both federal and state claims.

Summary of the Judgment

Affirmed—no legal error or abuse of discretion in the district court’s:
- allowance of the late-pleaded joint-enterprise affirmative defense,
- jury instructions on joint enterprise,
- application of Rule 601 rather than the Illinois Dead-Man’s Act, and
- exclusion of a Civilian Office of Police Accountability (COPA) report under Rule 403.
The court held that even if the jury had rejected joint enterprise (which it did), ample evidence supported a separate finding that Officer Ewing was not a proximate cause of plaintiffs’ injuries.
No reversible error arose from evidentiary rulings; any possible errors were harmless.

Detailed Analysis

A. Precedents Cited and their Influence

Grubb v. Illinois Terminal Co., 8 N.E.2d 934 (Ill. 1937)— classic Illinois authority that contributory negligence of one member of a joint enterprise is imputed to all. Seventh Circuit extended its logic to a criminal venture.
Erie R.R. v. Tompkins, 304 U.S. 64 (1938)—federal courts apply substantive state law; however, Seventh Circuit found no Illinois precedent forbidding criminal joint enterprises, so it filled the gap.
Restatement (Second) of Torts § 491—expansive definition of joint enterprise (“broader than partnership”) cited to rebut plaintiffs’ claim that only lawful ventures qualify.
Lovejoy Elecs. v. O’Berto, 873 F.2d 1001 (7th Cir. 1989) and Estate of Suskovich v. Anthem, 553 F.3d 559 (7th Cir. 2009)—key Rule 601 decisions relied on to hold that state competency rules yield to federal rules when testimony touches both federal and state causes of action.
Young v. James Green Mgmt., 327 F.3d 616 (7th Cir. 2003)— precedent supporting exclusion of investigative agency conclusions under Rule 403.

B. Court’s Legal Reasoning

Joint Enterprise Theory Permitted
The panel discerned no Illinois authority restricting joint enterprise to lawful “business” ventures. Language such as “common business interest” merely distinguishes purposeful ventures from casual ride-sharing. Using Grubb and the Restatement, the court held that an illegal profit-seeking objective (the robbery) suffices. Because evidence showed at least “more than a scintilla” of agreement, common purpose, possible shared proceeds, and mutual control opportunities, the defense was properly tried.
Rule 601 Supersedes the Illinois Dead-Man’s Act
Testimony about decedent Arrington’s actions related to both federal (§ 1983 excessive-force) and state claims. Following Donohoe and Estate of Suskovich, the panel held that where evidence overlaps causes of action, the “rule of decision” is partly federal, so the state competency statute does not apply. Rule 601’s default of competence governs.
Exclusion of COPA Report under Rule 403
The report’s narrative conclusions risked unfair prejudice and confusion. Plaintiffs introduced the same underlying factual materials through experts; thus probative value was marginal. “Door-opening” by Officer Ewing was cured by striking testimony and jury instruction—measures within the trial court’s discretion.
Harmless-Error Doctrine
Even assuming arguendo error in any ruling, none had a “substantial effect” on the verdict. The jury rejected joint enterprise but could still find for defendants on proximate-cause or precaution theories.

C. Likely Impact of the Decision

Expanded Defense Arsenal in Illinois Tort & § 1983 Litigation
Defendants may now confidently plead joint-enterprise contributory negligence when plaintiffs were accomplices in criminal conduct—potentially broadening summary-judgment and trial strategies.
Clarifies Federal–State Competency Clash
Litigants cannot invoke the Illinois Dead-Man’s Act to bar testimony if that testimony is relevant to any federal claim in the case; Rule 601 controls. Counsel must reassess evidentiary objections accordingly.
Affirms Caution Toward Investigative Agency Reports
Trial courts retain wide discretion to exclude administrative findings (e.g., COPA, EEOC, internal affairs) where factual foundations can be presented through direct evidence and expert testimony.
Strategic Discovery Cues
Plaintiffs wishing to counter a potential “criminal joint enterprise” label must develop clear evidence of dissent, withdrawal, or lack of mutual control to defeat the defense at Rule 50 stages.

D. Complex Concepts Simplified

Joint Enterprise: Think of it as a temporary partnership for a shared goal. If you and friends knowingly set out together to gain something—lawful or unlawful—and each can influence the driver, all are legally treated as co-drivers. Any driver’s negligence becomes everyone’s negligence.
Contributory Negligence (Illinois pre-1986 cases): A plaintiff’s own fault that helps cause the injury bars or reduces recovery. Although Illinois adopted comparative fault, contributory negligence still appears through doctrines like joint enterprise that impute fault.
Illinois Dead-Man’s Act: A 19th-century rule banning testimony about conversations or events with someone who has died, intended to prevent perjury when the decedent cannot rebut. Rule 601 can override it in federal court.
Opening the Door: A witness’s statement that injects an excluded topic may allow the opposite party to introduce otherwise barred evidence to correct a misleading impression, but the trial judge decides the scope of that remedy.

Conclusion

Cokes v. City of Chicago solidifies two doctrinal points within the Seventh Circuit: (1) the joint-enterprise doctrine of contributory negligence is not confined to respectable business outings but extends to criminal escapades, and (2) Rule 601’s presumption of competency overrides Illinois’ Dead-Man’s Act whenever testimony bears on federal claims. By also reaffirming broad discretion under Rule 403, the decision equips trial courts with clear guidance on managing mixed federal/state tort trials arising from police actions. Practitioners must now navigate these clarified evidentiary and liability landscapes when framing defenses and crafting trial strategies.