The border wall was a central promise of Trump's campaign for the White House four years ago and bid this year for a second term.
Lawmakers said they received a request on Thursday to reprogram more than $3.8 billion from funding for the National Guard and weapons programs, setting the stage for a possible confrontation with Democrats.
Congressional Democrats, who opposed Trump's past diversion of billions of dollars in military spending to the border wall project, said the decision was dangerous and misguided.
"Congress has not authorized this money. So Donald Trump doesn't get to look at it like his personal bank account, and he'll just move a little cash around. This is wrong, it violates separation of powers and one more time - it makes Donald Trump act as if he believes he is above the law," Warren told a reporter in North Charleston on Friday (February 14).