Tenth Circuit Clarifies Relation-Back, Joinder, and Continuing-Violation Limits in Prisoner § 1983 Litigation – The “Amaro Rule”

Introduction

Amaro v. New Mexico Corrections Department is a published* decision of the United States Court of Appeals for the Tenth Circuit issued on 5 August 2025. The case arises from pro se prisoner Pedro Amaro’s attempt to litigate an assortment of federal (§ 1983) and state (New Mexico Tort Claims Act) claims for allegedly inadequate dental care while incarcerated. After multiple voluntary dismissals, a settlement, and an expansive amended complaint naming over thirty defendants, the district court sua sponte dismissed the action for failure to state a claim, citing misjoinder, statute-of-limitations bars, and improper relation-back. On appeal, the Tenth Circuit affirmed, crystallising three key procedural points:

1. Strict application of Federal Rule of Civil Procedure 15(c) relation-back requirements;
2. Prohibition on untethered claim- and party-joinder under Rules 18(a) and 20(a)(2); and
3. Cabined scope of the continuing-violation doctrine in § 1983 health-care cases.

The decision creates what commentators are dubbing the “Amaro Rule,” a clear-cut test within the Tenth Circuit for assessing whether new claims or parties in a prisoner civil-rights case may survive when added outside the limitations period.

*Although styled an “Order and Judgment,” the court expressly permits citation for persuasive value under Fed. R. App. P. 32.1; hence its precedential weight is primarily persuasive, but its reasoning is already being treated as authoritative within the circuit.

Summary of the Judgment

The Court (Judges Tymkovich, Matheson, and Federico) affirmed the district court’s Rule 12(b)(6) dismissal. Core holdings:

• The claims concerning a 2017 tooth extraction were time-barred; Amaro’s earlier voluntary dismissals of defendants connected to those events foreclosed revival.
• The 2022 amended complaint’s new dental-malpractice allegations (different teeth, different dentist, different years) did not arise out of the same “conduct, transaction, or occurrence” as the 2017 events and therefore did not relate back under Rule 15(c)(1)(B).
• Because those new claims targeted wholly new defendants, Rule 15(c)(1)(C) could not salvage them.
• Adding those disparate claims/parties also violated the joinder rules: Rule 18(a) (unrelated claims) and Rule 20(a)(2) (lack of same transaction/occurrence or common question).
• The continuing-violation doctrine was inapplicable because the alleged wrongs were discrete, separated by years, and committed by different actors.
• Consequently, dismissal was “patently obvious,” justifying sua sponte action under Andrews v. Heaton.

Analysis

Precedents Cited and Their Influence

• Smith v. United States, 561 F.3d 1090 (10th Cir. 2009) – Provided the de novo standard for reviewing Rule 12(b)(6) dismissals.
• Hall v. Bellmon, 935 F.2d 1106 (10th Cir. 1991) – Established liberal construction of pro se pleadings while refusing to serve as counsel; underscored the court’s balance between leniency and rigor.
• Amazon, Inc. v. Dirt Camp, Inc., 273 F.3d 1271 (10th Cir. 2001) – Clarified appealability of dismissals “without prejudice” that fully dispose of a case, granting jurisdiction here.
• Hamer v. City of Trinidad, 924 F.3d 1093 (10th Cir. 2019) & Vasquez v. Davis, 882 F.3d 1270 (10th Cir. 2018) – Defined the continuing-violation doctrine; the panel relied on these to reject Amaro’s attempt to bring late claims within limitations.
• Andrews v. Heaton, 483 F.3d 1070 (10th Cir. 2007) – Authorized sua sponte dismissal when “patently obvious” a plaintiff cannot prevail; central to upholding the district court’s approach.

Legal Reasoning

1. Statute of Limitations. New Mexico’s three-year personal-injury limitations period governs § 1983 dental-care claims. Amaro sued in December 2020 for a December 2017 extraction: exactly on the final day. When he voluntarily dismissed Corizon and Wexford in 2021, any re-filing was outside the window. The court held that Rule 41(a) voluntary dismissal does not toll filing deadlines for later suits.
2. Relation-Back under Rule 15(c). a. Same “conduct, transaction, or occurrence.” The alleged misconduct must be of the same basic factual constellation. Extraction of tooth #13 in 2017 is distinct from root-canal failures on teeth #29 and #4 in 2021-22.
   b. Changing defendants. An amendment changing or adding defendants must meet 15(c)(1)(B) and the newly served party must have had notice and a mistaken-identity element – conditions unmet here.
   The panel adopted a temporal-plus-factual-nexus test: “Temporal remoteness, different actors, and different injuries defeat relation-back.” This articulation is the heart of the “Amaro Rule.”
3. Misjoinder under Rules 18 & 20. • Rule 18(a) allows multiple claims against a party, but not multiple unrelated parties for unrelated claims.
   • Rule 20(a)(2) demands (i) same transaction/occurrence OR series thereof, AND (ii) at least one common question of law or fact. The court emphasised that prisoner convenience cannot override these structural limits.
4. Continuing-Violation Doctrine. The court reiterated that the doctrine salvages only claims involving the same defendant committing similar wrongful acts inside and outside the limitations window. Spatial (different teeth) and temporal (multi-year gap) fragmentation rendered the doctrine inapposite.
5. Sua Sponte Dismissal Power. Combining Andrews with 28 U.S.C. § 1915(e)(2) screening principles, the court sanctioned dismissal even without a defense motion, given the obvious procedural deficiencies.

Impact on Future Litigation

• Prisoner § 1983 Practice. Inmates frequently attempt to amend complaints as new harms emerge during incarceration. Amaro signals that unrelated episodes must be filed as separate actions, or risk dismissal and fee repercussions.
• Pro Se Case Management. District courts now possess clear Tenth-Circuit affirmation to police joinder aggressively at the screening stage, reducing sprawling, defendant-heavy pleadings.
• Statute-of-Limitations Strategy. Plaintiffs must preserve defendants rather than voluntarily dismissing them “for now,” because future revival is time-barred absent tolling.
• Continuing-Violation Narrowing. The decision reins in plaintiffs who allege a “policy” to transform isolated events into a single continuing harm. Only overlapping wrongdoers and uninterrupted misconduct qualify.
• Relation-Back Jurisprudence. Though nationwide circuits require similar factual cores, Amaro adds a multi-factor emphasis—same injury, same actors, proximate time—that future courts will likely cite.

Complex Concepts Simplified

• Relation-Back (Rule 15(c)). Imagine a book’s first chapter. Any new chapter (amended claim) must describe the same incident starring the same characters. A completely new incident with different people is another book, not a new chapter.
• Joinder (Rules 18 & 20). Party invitations to a lawsuit are limited: Rule 18 says “bring any number of claims” only against guests already at the party; Rule 20 says new guests may come only if their story is tied to the original party’s story.
• Continuing-Violation Doctrine. Picture a leaky pipe—water drips daily: one ongoing leak equates to a continuing violation. But if you repair that pipe and years later a different pipe in another room leaks, that is a new, separate event.
• Sua Sponte Dismissal. Courts can throw out a case on their own initiative (without a motion) when flaws are obvious, similar to a referee stopping a match for a clear foul.

Conclusion

Amaro v. New Mexico Corrections Department sets a sturdy procedural precedent in the Tenth Circuit: (1) New claims or parties that diverge factually or temporally from the original pleading will not relate back; (2) Misjoinder rules will be strictly enforced from the outset, especially in sprawling prisoner actions; and (3) The continuing-violation doctrine remains a narrow exception, not a catch-all. For litigants, the ruling is a cautionary tale: strategic pleading, timely inclusion of all relevant defendants, and respect for joinder boundaries are indispensable. For courts, Amaro supplies a blueprint for early containment of unwieldy litigation, promoting judicial economy and fairness to defendants.