President Donald Trump and his administration will not participate in the Congressional impeachment inquiry, the White House announced Tuesday, setting up a constitutional crisis in the conflict between two ostensibly co-equal branches of government.

"But seriously folks this is actually a constitutional crisis."

—Leah Greenberg, Indivisible

"There is no legal basis for Trump's position," tweeted NBC analyst Katie Phang. "Hard stop."

"The Trump administration's flat refusal to cooperate with congressional oversight is, itself, impeachable," tweeted Vox's Ezra Klein.

NEW



9-page letter just released from the White House claims impeachment inquiry is illegitimate and Trump Administration won’t cooperate or participate in the process.



There is no legal basis for Trump’s position. Hard stop. https://t.co/Sm34aqYTuH — Katie Phang (@KatiePhang) October 8, 2019

The news sparked a call from Credo Action co-director Heidi Hess for immediate impeachment.

"It's absolutely outrageous that Donald Trump sent a letter to Congress informing them that he is above the Constitution and every law in America," said Hess. "House Democrats need to move immediately and use all the power at their disposal to compel testimony and delivery of documents, hold administration officials accountable for their contempt of Congress, and draft articles of impeachment that span all of Trump's crimes."

"If Speaker Pelosi and leadership continue to drag their feet, they are giving tacit approval of the ridiculous arguments laid out in the White House counsel's letter," Hess added. "We can't wait any longer."

White House Press Secretary Stephanie Grisham said in a statement that the administration would not cooperate with the inquiry and seemingly closed the door on any negotiations.

"The Executive Branch cannot be expected to, and will not participate in, this exercise of partisan political theater," said Grisham.

MORE: Statement from @PressSec on today’s letter rejecting the House’s authority to impeach @realDonaldTrump. pic.twitter.com/MFpC6bGEbb — Andrew Feinberg (@AndrewFeinberg) October 8, 2019

As NBC reported Tuesday, the inquiry is not baseless: