Senate Republicans on Thursday blocked a Democratic effort to end the US war with Iran, voting 49-50 against a House-passed war powers resolution as the conflict passed the 200-day mark, with 19 American service members killed.

The measure passed the House earlier with bipartisan support. Senate Democrats, led by the minority leader, Chuck Schumer, and the senator Andy Kim of New Jersey, forced the vote under the War Powers Resolution, which allows lawmakers to bring such measures to the floor.

In June, the Senate adopted a similar House-passed resolution 50-48, with four Republicans – Bill Cassidy, Susan Collins, Lisa Murkowski and Rand Paul – voting in favor. But a month later, after the ceasefire collapsed, the chamber voted 47-49 against advancing a legally binding joint resolution, with Collins the only Republican in support.

After the vote, Ron Wyden, the Democratic senator from Oregon, ack...