According to https://www.cjr.org/covering_trump/viral-nancy-pelosi-photo-clap.php, one photographer from The New York Times was given exclusive photography privileges for this federal government event:
...New York Times White House photographer Doug Mills was appointed pool photographer for the State of the Union—a designation that meant he would be the only photographer allowed on the House floor during the event...
That would incline me to think it should be a government record, but since it was taken by a photographer for a private news organization, I'm left uncertain.
So, to rehash: Is the Pelosi-Trump "f-you clap" State of the Union photo in the public domain? If copyrighted, would modifying it into a form of satire allow one to skirt the copyright restrictions?