Washington DC [US], July 15 : US Senate Democrats on Tuesday (local time) blocked an USD 1.15 trillion Pentagon policy bill, opposing its advancement over concerns about US President Donald Trump's handling of the Iran war and seeking greater restrictions on the administration's military actions, Politico reported.
According to Politico, the National Defence Authorisation Act (NDAA) failed to secure the 60 votes required to move forward to Senate debate, with the procedural vote ending 50-46.
All Democrats present voted against advancing the legislation.
The move dealt a setback to Republicans, who had sought approval of the defence policy bill as part of efforts to advance Trump's record-level defence budget proposals.
The NDAA is one of the few major pieces of legislation that traditionally passes Congress every year.
According to Politico, Democrats had indicated for months that they would not support the Pentagon legislation without additional safeguards on presidential war powers, particularly regarding the US military campaign against Iran.
Senate Majority Leader John Thune and other Republican lawmakers argued that blocking the bill amounted to politicising national security, while Democrats maintained that the legislation should include limits on the administration's actions.
Senate Minority Leader Chuck Schumer criticised the bill's advancement without restrictions on the Iran conflict.
"The NDAA cannot become a permission slip for that recklessness that we see occurring in Iran," Schumer said, as quoted by Politico.
"Donald Trump does not get to drag the American people deeper into a war he cannot explain and does not know how to end, and then demand Congress look the other way," he added.
The Senate has failed multiple times to advance its own version of the NDAA amid partisan disagreements.
However, it is considered rare for one party to prevent the chamber from even beginning debate on the annual defence legislation.
The last instance occurred more than 15 years ago, when Senate Republicans blocked Democratic-led defence legislation over a proposal to repeal the military's "don't ask, don't tell" policy.
The latest standoff comes as lawmakers in both chambers signal that the traditionally bipartisan defence bill could become a major political battleground.
Democrats have criticised the proposed USD 1.15 trillion defence allocation, describing it as part of Trump's broader USD 1.5 trillion defence budget request, while arguing that more attention should be given to domestic priorities and reducing costs for Americans, as reported by Politico.
The dispute also comes amid renewed US military action against Iran after Trump declared the end of a months-long ceasefire and the United States resumed strikes.
Republicans have largely supported the defence bill, but lawmakers remain concerned about the potential economic impact of continued military operations, including possible effects on fuel prices ahead of the midterm elections.
Beyond the defence budget request, lawmakers are also considering a White House request for an additional USD 67 billion to cover costs linked to the Iran war.
During the Senate Armed Services Committee's closed-door markup last month, only four of the 13 Democratic members supported the bill, including Senator Jack Reed of Rhode Island, the committee's ranking Democrat. However, all four voted against advancing the legislation on the Senate floor.
Senate Majority Leader John Thune changed his vote from "yes" to "no" in order to preserve the ability to bring the bill up again through a motion to reconsider, as reported by Politico.
Four senators did not participate in the vote, including Republicans Jim Justice of West Virginia and Mitch McConnell of Kentucky, and Democrats John Fetterman of Pennsylvania and Alex Padilla of California, Politico reported.
Republicans highlighted provisions in the bill, including a 3.6 per cent pay increase for troops, expanded drone technology development and major investments in shipbuilding.