legislation_cosponsors: 119-sres-397, M001176

Cosponsors for tracked legislation. Distinguishes original cosponsors (signed on at introduction) from later additions. Linked to congress_members via bioguide_id.

This data as json

bill_id	bioguide_id	full_name	party	state	sponsorship_date	is_original_cosponsor
119-sres-397	M001176	Sen. Merkley, Jeff [D-OR]	D	OR	2025-09-17	1