Definition
The American Clause is a provision in a marine insurance policy protecting the original insurer's full liability exposure regardless of any subsequent insurance obtained by the insured on the same risk. Specifically, it states that if the insured later procures additional coverage on the same subject matter, the first insurer remains liable for the full amount it subscribed and cannot seek contribution from the later underwriters.
This clause inverts the default rule of contribution among co-insurers. Under ordinary insurance law principles, when multiple policies cover the same loss, each insurer bears a proportionate share of the liability. The American Clause overrides that default: the first insurer pays in full and cannot turn to subsequent underwriters for relief. The clause effectively treats subsequent insurance as irrelevant to the first insurer's obligation.
Common Confusion
The American Clause should not be confused with general double insurance or co-insurance rules, which contemplate ratable contribution among insurers covering the same risk. It also should not be conflated with subrogation, which concerns the insurer's right to step into the insured's shoes against a third-party tortfeasor. The American Clause operates exclusively at the level of insurer-to-insurer allocation and only in the specific posture of sequential, not concurrent, coverage.
Why It Matters in Research
Researchers will encounter the American Clause almost exclusively in historical marine insurance materials. It reflects a doctrinal moment when American courts and underwriters were actively diverging from English insurance practice, particularly on the contribution question. By the late nineteenth century, English policies typically allowed first insurers to seek ratable contribution from subsequent underwriters; the American Clause was the American market's answer, locking in full first-insurer liability.
The practical research trap is temporal: the clause was a live term of art in the nineteenth-century marine insurance trade and appears in period case law and treatises, but it has largely disappeared from modern insurance vocabulary. A researcher working in contemporary insurance law who encounters this term in a historical document should resist mapping it onto modern contribution or coordination-of-benefits doctrines, which operate under different frameworks and regulatory regimes.
Because the clause is tied to marine insurance specifically, it will not appear in fire, casualty, or life insurance materials from the same era. Researchers surveying general insurance law histories who do not find this clause in non-marine sources should not infer absence from the doctrine — the clause simply did not travel across insurance lines.
The clause also signals something about forum and jurisdiction. The leading case cited in both Black's editions — American Ins. Co. v. Griswold, 14 Wend. (N.Y.) 399 — is a New York decision, and New York was the center of American marine underwriting in this period. Researchers should expect the heaviest concentration of American Clause litigation and commentary in New York sources.
Historical Dictionary Support
Both editions of Black's Law Dictionary define the American Clause in nearly identical terms, confirming doctrinal stability between the first and second editions. The second edition adds the full case citation — American Ins. Co. v. Griswold, 14 Wend. (N.Y.) 399 — which the first edition omits, referencing only the volume and reporter. This is a useful bibliographic clarification: the Wendell reporter is a New York Supreme Court reporter covering the 1820s–1840s, situating the clause's formal articulation in early American marine insurance litigation.
Neither edition elaborates on the clause's relationship to English practice or explains why "American" was chosen as the label. Historical insurance treatises of the period — including works by Theophilus Parsons on marine insurance — would provide fuller doctrinal context that the dictionary entries do not supply. Researchers should treat the Black's entries as a starting point and expect the treatise literature to carry more analytical weight.
Both editions embed the clause definition within marine insurance context without hedging about other applications, reinforcing that this is a domain-specific term with no recognized extension beyond marine coverage.
Jurisdictional Note
The clause originates in New York marine insurance practice and the principal authority is a New York decision. Whether courts in other American jurisdictions adopted or applied the clause on identical terms is not clearly established in the standard dictionary sources. Researchers working outside New York should not assume uniform application across states.
Encyclopedia Cross-Reference
No direct match in the Law Mind Encyclopedia. The closest adjacent entry for background on American-rule cost allocation principles generally is: Attorneys' Fees — American Rule and Exceptions (The Law Mind Civil Procedure & Evidence Encyclopedia, civpro_137), though that entry addresses fee-shifting doctrine rather than insurance contribution and should not be read as substantively related to the American Clause.