With Republicans in the Senate considering legislation that would reign in presidential powers, Ms Pelosi said that the bill would only serve to give Mr Trump a “pass” for his emergency declaration to build his US-Mexico border wall.
“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 in a statement. “The house will not take up this legislation to give President Trump a pass.”
The warning comes just as the Senate is set to vote on a resolution that would nullify Mr Trump’s emergency declaration.
It appears as though there are enough Republicans in that chamber who plan on voting with Democrats to put a halt on the declaration, which would force the first veto of the Trump presidency.
It does not appear as though Congress would have enough support for the resolution to override that veto, however.
Democrats have argued that the emergency declaration violates the US Constitution, noting that Congress itself chose not to allocate funding for the wall earlier this year.
The bill faces several legal challenges across the country, too.