The promise was to co-sponsor Sen. Van Hollen's Polluters Pay Climate Fund Act, which taxes the largest historical fossil-fuel emitters to fund climate mitigation. Van Hollen introduced it as S.25 (Polluters Pay Climate Fund Act of 2025) in the 119th Congress. Verification: BillTrack50 (a cited source I fetched successfully) confirms the bill identity and lists "Angela Alsobrooks (D)" in the Sponsors section alongside six other legislators. An independent web search corroborates Alsobrooks as a cosponsor of S.25 (Van Hollen sponsor; Markey, Merkley, Sanders, Warren, Welch also cosponsors). This is FULL rather than CHAMPIONED because Van Hollen authored and led the bill; Alsobrooks added her cosponsorship as pledged rather than leading it — consistent with the original introduction naming Van Hollen for himself with Sanders, Merkley, Markey, and Warren (she joined later). Caveat on sourcing: the cited GovTrack cosponsors page (which the rating quoted for the exact Jan. 22, 2025 join date) and the cited Congress.gov bill text both returned HTTP 403 to automated fetches, so I could not directly verify the specific join date or the verbatim introduction line. However, the core promised outcome — that Alsobrooks cosponsored this specific Van Hollen bill — is independently confirmed by a reachable cited source (BillTrack50) plus corroborating search, so the FULL rating is supported and not overstated. Confidence trimmed from 0.95 to 0.90 to reflect that two of the three cited URLs were unreachable to me.