How many US Presidents actually faced impeachment?

the answer is TWO....

Two U.S. Presidents have been impeached, Andrew Johnson, and Bill Clinton. Both were acquitted at trial. Ever since Johnson's trial, there has been an established precedent against impeachment of a president solely on political grounds.

Richard Nixon resigned in the face of the near certainty of his impeachment, which had already been approved by the House Judiciary Committee.

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In politics... never retreat, never retract... never admit a mistake.