119-HR-1366 DC Insider Whip Count Analysis

Breakdown: expected support/opposition by party and caucus

- Chamber control: Republicans hold the House and Senate; Senate rules (filibuster) remain intact. [7]Wikipedia — 119th United States Congress (party control context)[6]Office of Sen. John Thune — Thune delivers first remarks as Senate Majority Lea…

• House GOP conference: Strong support. The rule for H.R. 1366 was adopted 215–209 under a closed rule, indicating near‑unified Republicans willing to bring the bill to the floor with limited amendment exposure. [1]House Republican Cloakroom — Tuesday December 16th 2025 - Republican Cloakroom…[8]Congress.gov — Congressional Record Daily Digest (rule terms for H.R. 1366)
• House Democrats: Broad opposition from leadership‑aligned environmental groups (e.g., LCV letter urging a NO vote) and dissenting views in the committee report; exception: Rep. Horsford (NV) is an original cosponsor. Net: mostly NO, with a small Nevada carve‑out. [9]League of Conservation Voters — LCV letter urging opposition to H.R. 1366 and r…[2]Congress.gov — H. Rept. 119-386 - Mining Regulatory Clarity Act (report text)[3]Congress.gov — H.R. 1366 cosponsors (119th Congress)
• House committee signal: Natural Resources ordered the bill reported 25–17, foreshadowing a largely party‑line floor. [2]Congress.gov — H. Rept. 119-386 - Mining Regulatory Clarity Act (report text)
• Senate Republicans: Favorable posture. The Senate companion (S.544) was reported favorably by ENR (GOP‑led), and Majority Leader Thune has kept the filibuster, implying 60 votes required on the floor. [4]Congress.gov — S.544 all actions (ENR reported favorably)[10]Congress.gov — S.Res. 26 (majority party committee memberships; ENR Chair Mike…[6]Office of Sen. John Thune — Thune delivers first remarks as Senate Majority Lea…
• Senate Democrats/Independents: Institutional resistance from mining‑reform advocates (e.g., ENR Ranking Member Heinrich backs a different reform approach), but notable support from Nevada Democrats Cortez Masto and Rosen as S.544 cosponsors. Expect most Democrats NO absent packaging; Nevada Democrats and a few resource‑state moderates are potential YES. [11]House Natural Resources Democrats — House NR Democrats press (Grijalva/Heinrich…[5]Congress.gov — S.544 cosponsors (Cortez Masto, Risch, Rosen, Crapo, Murkowski)
• Interest‑group landscape: Proponents include the National Mining Association and Nevada Mining Association; opponents include Earthworks and LCV. Expect these signals to reinforce party lines, with regional exceptions. [12]National Mining Association — NMA applauds House action (includes support for M…[13]U.S. Senate (Cortez Masto) — Cortez Masto–Risch press release with NV Mining As…[14]Earthworks — Earthworks press statement opposing Mining Regulatory Clarity Act[9]League of Conservation Voters — LCV letter urging opposition to H.R. 1366 and r…

Key legislators and pivotal votes

Focus on members with procedural leverage or cross‑pressure from state mining economies.

• House: Sponsor Rep. Mark Amodei (R‑NV) and original cosponsor Rep. Steven Horsford (D‑NV). Their bipartisan Nevada pairing reduces intra‑delegation friction and provides at least one Democratic vote. [16]Office of Rep. Mark Amodei — Amodei press release reintroducing H.R. 1366 with…[3]Congress.gov — H.R. 1366 cosponsors (119th Congress)
• House: Chair Bruce Westerman (R‑AR), Natural Resources, has already delivered the bill from committee; under the closed rule, the chair and Rules are minimizing amendment risk. [2]Congress.gov — H. Rept. 119-386 - Mining Regulatory Clarity Act (report text)[8]Congress.gov — Congressional Record Daily Digest (rule terms for H.R. 1366)
• Senate: ENR Chair Mike Lee (R‑UT) advanced the companion; Ranking Member Martin Heinrich (D‑NM) champions alternative mining‑law reforms, positioning him as a leading opponent on substance. [10]Congress.gov — S.Res. 26 (majority party committee memberships; ENR Chair Mike…[11]House Natural Resources Democrats — House NR Democrats press (Grijalva/Heinrich…
• Senate swing Democrats: Sens. Catherine Cortez Masto (D‑NV) and Jacky Rosen (D‑NV) are cosponsors, making them core crossover votes; additional Democratic votes would be needed to reach 60 unless packaged. [5]Congress.gov — S.544 cosponsors (Cortez Masto, Risch, Rosen, Crapo, Murkowski)
• External pressure points: Pro‑mining endorsements (NMA, Nevada Mining Association) versus opposition from Earthworks/LCV will weigh most on Western Democrats and a handful of Northeastern Republicans in both chambers. [12]National Mining Association — NMA applauds House action (includes support for M…[13]U.S. Senate (Cortez Masto) — Cortez Masto–Risch press release with NV Mining As…[14]Earthworks — Earthworks press statement opposing Mining Regulatory Clarity Act[9]League of Conservation Voters — LCV letter urging opposition to H.R. 1366 and r…

Leadership influence and procedural dynamics

Leadership control and floor procedure are decisive for timing and outcome.

• House: Speaker Mike Johnson and Majority Leader Steve Scalise set the bill on the floor via H. Res. 951; the closed rule de‑risks floor consideration and limits Democrats to a motion to recommit. Expect a quick, largely party‑line vote. [17]Congress.gov — On the House Floor on December 16, 2025 (H. Res. 951 coverage)[1]House Republican Cloakroom — Tuesday December 16th 2025 - Republican Cloakroom…
• House vote proxy: Adoption of the rule (215–209) is a strong predictor of final passage in a narrow‑majority House, absent late defections. [1]House Republican Cloakroom — Tuesday December 16th 2025 - Republican Cloakroom…
• Senate: Majority Leader John Thune controls the floor but has affirmed preserving the 60‑vote threshold. As a result, standalone passage likely requires a bipartisan deal or folding S.544 into a broader energy/permitting package. [6]Office of Sen. John Thune — Thune delivers first remarks as Senate Majority Lea…
• Committee leverage: The Senate ENR majority is Republican; S.544 already cleared ENR favorably, simplifying the path to floor consideration once leadership finds an appropriate vehicle. [4]Congress.gov — S.544 all actions (ENR reported favorably)

Assessment: likelihood of passage

Bottom‑line call grounded in current alignments, rules, and public positions.

• House: High likelihood. Evidence: committee report (25–17), closed rule, and rule adoption 215–209. Expect a narrow, mostly party‑line passage with at least one Democratic YES (Horsford). [2]Congress.gov — H. Rept. 119-386 - Mining Regulatory Clarity Act (report text)[8]Congress.gov — Congressional Record Daily Digest (rule terms for H.R. 1366)[1]House Republican Cloakroom — Tuesday December 16th 2025 - Republican Cloakroom…[3]Congress.gov — H.R. 1366 cosponsors (119th Congress)
• Senate: Moderate overall, conditional on packaging. Evidence: S.544 reported favorably; Nevada Democrats co‑sponsor; but 60‑vote threshold remains the binding constraint. Standalone prospects low‑to‑moderate; inclusion in a larger permitting/energy package lifts prospects to moderate. [4]Congress.gov — S.544 all actions (ENR reported favorably)[5]Congress.gov — S.544 cosponsors (Cortez Masto, Risch, Rosen, Crapo, Murkowski)[6]Office of Sen. John Thune — Thune delivers first remarks as Senate Majority Lea…

Sourcing highlights

Core documents underpinning this whip analysis.

1. House committee report and history for H.R. 1366. [2]Congress.gov — H. Rept. 119-386 - Mining Regulatory Clarity Act (report text)[18]Web search · turn 10 #4
2. House floor rule and votes (H. Res. 951). [17]Congress.gov — On the House Floor on December 16, 2025 (H. Res. 951 coverage)[1]House Republican Cloakroom — Tuesday December 16th 2025 - Republican Cloakroom…
3. Senate companion S.544: actions and cosponsors. [4]Congress.gov — S.544 all actions (ENR reported favorably)[5]Congress.gov — S.544 cosponsors (Cortez Masto, Risch, Rosen, Crapo, Murkowski)
4. Senate leadership/filibuster posture. [6]Office of Sen. John Thune — Thune delivers first remarks as Senate Majority Lea…
5. Stakeholder positions (support and opposition). [12]National Mining Association — NMA applauds House action (includes support for M…[13]U.S. Senate (Cortez Masto) — Cortez Masto–Risch press release with NV Mining As…[14]Earthworks — Earthworks press statement opposing Mining Regulatory Clarity Act
6. Underlying legal driver: Ninth Circuit Rosemont decision. [15]Justia — Center for Biological Diversity v. U.S. FWS (9th Cir. 2022) – Rosemont…

Key metrics