Donald Trump's effort to freeze trillions of dollars in federal grants is the most provocative of his many attempts to expand his power in the first days of his presidency.

Congressional Democrats and good-government groups say President Donald Trump's Monday night directive to pause the distribution of trillions of dollars in federal grants and loans represents an immense power grab that would upend the constitutional separation of powers between different branches of government.

Joyce Vance warned that Trump's move could ignite a "constitutional confrontation" between government branches.