§ 10004.Effect of unconstitutionality in part.

CPLR 10004 addresses what happens when part of the CPLR is challenged and loses. If any clause, sentence, paragraph, subdivision, section, rule, or part of 'this chapter' is adjudged invalid by a court of competent jurisdiction, that judgment does not affect, impair, or invalidate the remainder of the CPLR. Instead, the judgment is confined in its operation to the specific clause, sentence, paragraph, subdivision, section, rule, or part directly involved in the controversy that produced it.

This is a severability clause, a common feature of large statutes. Its purpose is to prevent one invalid provision from dragging down an entire code, and to remove any need for a court to guess whether the legislature would have wanted the rest of the law to survive a partial defeat. CPLR 10004 answers that question in advance: any invalidity ruling stays narrowly confined to the exact text that was litigated and decided.

The section does not immunize the CPLR from every future challenge. It only limits the scope of any single invalidity ruling to the provision the court decided; a different provision remains open to its own separate challenge, to be judged on its own terms.