Senate Minority Leader Charles Schumer (D-New York) said in a speech on the floor Monday that he will lead Democrats to block an upcoming spending bill if it includes funding for a border wall.
Schumer said funding for one of President Trump's marquee campaign promises would effectively be a "poison pill" for the "must pass" appropriations bill, the Washington Examiner reported.
A short-term plan to fund the federal government will expire sometime in April, so action must be taken to prevent an incident similar to the 2013 shutdown.
"It would be inappropriate in our judgement to insist on the inclusions of such funding," Schumer said.
Schumer said Trump has not answered enough questions about the specifics of his plan to build a wall along the United States-Mexico border:
"What's the design of the wall? Where's it going to be located? How is it going to be paid for?" he asked.
In a letter to Senate Appropriations Committee Chairman Thad Cochran (R-Mississippi), Schumer added that any stipulation withholding funds from Planned Parenthood or establishing a "deportation force" also would not be tolerated.
Republicans need eight Democrats to cross the proverbial aisle in order to break any filibuster of the bill.
Senate Majority Leader Mitch McConnell (R-KY) has already made it clear he's not buying Trump's oft-repeated promise that Mexico will pay for a new border wall.
"Uh, no," McConnell answered last week in a Politico interview when asked if Mexico will foot the bill for the project.