Republican Senator Mike Lee, who had been shopping a second bill that would keep the emergency declaration in effect temporarily, said on Wednesday the White House had said Trump would not support his proposal, so he would be voting on Thursday to end the emergency declaration.

“For decades, Congress has been giving far too much legislative power to the executive branch,” Lee said in a statement. “I will be voting to terminate the latest emergency declaration.”

The Utah lawmaker was the fifth Republican senator to say they back a measure passed by the Democratic-led House of Representatives to terminate Trump’s declaration. In the 100-seat Senate, votes from at least four Republicans are needed to pass the measure, along with all 45 Democrats and two independents.

Given Trump’s threat to veto the legislation, it is unlikely to become law.

“We’ll see whether or not I have to do the veto. And it will be, I think, all very successful, regardless of how it all works out, but it’s going to be very successful,” Trump told reporters on Wednesday.