"Republican Senators are proposing new legislation to allow the President to violate the Constitution just this once in order to give themselves cover", she said.
If Trump commits to signing legislation handcuffing future emergency declarations, more GOP senators might vote Thursday against a separate bill blocking his border emergency.
An administration official said Wednesday that the White House is skeptical there will be enough votes to head off a Senate defeat Thursday and is reluctant to back limits on future declarations unless a victory on the resolution is assured. Its fate is unclear.
Trump was referring to an interview published Monday in the Washington Post Magazine in which Pelosi, who returned to power after Democrats won decisively in last year's midterms, said, "I'm not for impeachment".
At the heart of the legislative battle is billions of dollars in funding for a wall along the U.S. -Mexico border that Trump is demanding but Congress has refused to fully provide.
GOP Sens. Mike Lee of Utah and Todd Young of IN were also IN discussions with the White House about related legislation that would curb the ability of future presidents to declare national emergencies.
In an attempt to stave off Senate passage - an embarrassing prospect for Trump - Republican senators have been pushing an alternative measure that would instead address concerns that Trump's powers under the National Emergencies Act are too broad. Without congressional approval, the declaration would be terminated.
Vice President Mike Pence, center, accompanied by his Chief of Staff Marc Short, second from left, leaves the U.S. Capitol building on Capitol Hill in Washington, Tuesday, March 12, 2019.
Under a 1976 law, presidents have wide discretion in determining when a national emergency has occurred.
The two spoke on condition of anonymity to reveal private conversations.
The White House says that Trump is within his rights to declare the national emergency and that opposing him will be seen as a vote against border security - which could play poorly in their home states.