Capitalize the amendment’s name

Warning²Federal courts, Illinois courts21st and 22nd editions

A numbered constitutional amendment is a proper name, so the ordinal and the noun both carry capitals in a sentence — “the Fifth Amendment”. The lowercase abbreviation belongs to citations.¹

1. 1R. 8(d)(ii) Exceptions; R. 8(c)(ii) Exceptions. Tables: R. 11 Constitutions; T16 Subdivisions.
2. 2A warning: the form is usually wrong under the rule in note 1, and context can justify it.