But the letter comes as the Senate failed to override Trump's veto of a resolution that would have nixed his emergency declaration to secure funding for the border wall. The resolution canceling the declaration initially passed the Senate last month with 54 votes.

Under the National Emergencies Act, Congress can force a vote on Trump's emergency declaration every six months. It was the second time Congress had voted to end the emergency declaration but failed to override a veto from Trump.

The Senate legislation would end future national emergencies after 30 days unless Congress voted to extend them. It was passed out of the Homeland Security and Governmental Affairs Committee in July.