Senate Republicans managed to reject what was the sixth bipartisan attempt on Thursday to limit President Donald Trump’s Iran war powers since the conflict began more than two months ago, but the results foreshadowed obstacles ahead from members of his party over a legal deadline.

The vote underscored growing Republican frustrations with the war ahead of Friday, the 60-day mark that under the War Powers Resolution of 1973 should compel Congress to either authorize or end U.S. involvement in foreign hostilities.