Can Congress Enforce Subpoenas?

The impeachment inquiry is entering a new, even more contentious phase. In a letter to House Democrats on Tuesday, White House Counsel Pat Cipollone wrote that President Trump "cannot participate in your partisan unconstitutional inquiry."

House Speaker Nancy Pelosi responded that any efforts to "hide the truth" will be further evidence of obstruction of justice.

Here & Now's Peter O'Dowd looks at what options Congress has for getting the White House to cooperate with the inquiry with Lisa Kern Griffin, a law professor at Duke University and a former federal prosecutor.