Play video content EXCLUSIVE TMZ.com

Congressman Jason Chaffetz not only has the power to subpoena the reported memo written by James Comey, he also could put his John Hancock on a subpoena for any White House tapes that might exist to either confirm or shoot down Comey's version.

The Chairman of the House Oversight Committee appeared Wednesday on "TMZ Live" and made it clear ... he's noodling over whether to fire off the legal docs that could force the hands of Trump and Comey.