American checks and balances will disappear if Congress doesn't 'stand up to a runaway executive': Ex-prosecutor
Joyce Vance (MSNBC/screen grab)

On Tuesday, following reports that President Donald Trump had successfully pushed former White House Counsel Don McGahn to defy congressional subpoenas to testify, former federal prosecutor Joyce Vance starkly laid out the threat to the rule of law on MSNBC's "The Beat" — and warned that Congress and the courts must use their oversight power to put a stop to it.

"We're watching a situation where the traditional view that we have three co-equal branches of government, that view that the founding fathers used to create our Constitution, we're moving forward into an era where that may not be how this government is configured going forward," said Vance.

"We have an attorney general who is on record as having a very expansive view of power," said Vance. "He now seems to be driving that truck a little bit, along with a president who has autocratic tendencies."

"And what we'll have to look for very carefully is whether the institutions are strong enough to hold," Vance continued ominously. "Whether the courts and the legislative branch can stand up to a runaway executive."

Watch below: