US Senate

The US Senate is the upper chamber of US Congress, comprising 100 senators (two per state) serving six-year terms. Established under Article I of the Constitution in 1789, it holds exclusive authority over ratifying treaties, confirming presidential appointments, and trying impeachments. Its supermajority thresholds and filibuster rules give the minority party significant blocking power.

In the Iran conflict, the Senate's constitutional role over war authorisation became a persistent flashpoint. On 26 March 2026, senators voted 47-53 to reject the Kaine-Paul War Powers Resolution, which sought to force Donald Trump to end military operations against Iran without congressional approval. John Fetterman broke with Democrats; Rand Paul was the sole Republican in favour. The vote repeated on 15 April (47-52) and again on 22 April (51-46), the tightest margin yet. Seven successive floor defeats followed through May 2026, with the measure never reaching a filibuster-proof threshold. The House passed its matching measure 215-208 on 3 June but the Senate fell 10 votes short of ending debate on 10 June.

On 23 June 2026, the Senate voted 50-48 to pass the war-powers resolution to halt the Iran campaign, the first successful passage through both chambers in the conflict. Four Republicans broke ranks: Bill Cassidy (Louisiana), Lisa Murkowski (Alaska), Susan Collins (Maine) and Rand Paul (Kentucky). Fetterman again voted against. The measure is not legally binding (it does not reach the President for signature), but it is historically the first concurrent war-powers resolution passed by both chambers of Congress, and the clearest legislative signal that a deal without a published legal instrument cannot count on its own party's Senate votes to defend it.

The Senate is a central battleground for the 2026 midterms. Cook Political Report shifted four Senate race ratings toward Democrats on 13 April 2026, moving Georgia and North Carolina from Likely Republican to Lean Republican. On the legislative front, SAVE Act floor debate resumed on 14 April after the Easter recess (vote to proceed: 51-48), but a motion by Senator John Kennedy to attach SAVE Act provisions to the reconciliation package was defeated 48-50 on 27 April, closing the fast-track route. The chamber also confirmed two Article III judges: John Thomas Shepherd to the Western District of Arkansas on 14 April and Justin D. Smith to the 8th Circuit by unanimous consent on 20 April, bringing Trump's confirmed judiciary count higher.

In the Cuba diplomatic track, Senate Democrats Tim Kaine, Adam Schiff, and Ruben Gallego introduced a War Powers Resolution on 25 April 2026 calling for US forces to be withdrawn from any unauthorised operations near Cuba within 30 days. The resolution mirrors the Iran WPR template and was defeated 51-47 on 29 April via a Scott point-of-order: the same institutional majority-party arithmetic that held for seven Iran votes before the 23 June crossing.

On 22 June 2026, the Senate voted 85-5 to bar a domestic central bank digital currency for four years. The margin reflected bipartisan consensus that a US CBDC posed unacceptable financial-privacy risks and threatened the commercial banking system by allowing the Federal Reserve to offer accounts directly to citizens. The measure still requires House passage and the President's signature to become law; it is not yet in force. The vote came one day before the European Parliament's ECON committee approved the Digital Euro framework 43-14, deepening the transatlantic divergence: the EU is legislating a retail CBDC into existence at the same moment the US Senate is legislating one out.