"This is what I don't understand about the president. This was just a dumb idea," Gingrich said while appearing on "The View" Tuesday.
"Don't try to defend it," he added. "The idea that you could say, 'Oh, hi, we're going to have a meeting of seven major countries on my golf course' — and not have everybody else in the country go, 'What?'" Gingrich said, apparently mocking Trump.
Co-host Abby Huntsman suggested the incident showed that Trump didn't ask advisers whether his proposal was crazy. Gingrich argued that Trump probably did, but ignored his advisers' objections.
Trump announced on Saturday that he would begin looking for another site, blaming Democrats and the media for his decision.
Democratic lawmakers had introduced legislation restricting funding for the event and requiring Trump to disclose documents related to his decision.
Gingrich also backed Congress' decision to challenge Trump on the issue.
"The Congress ought to have independent judgment. I thought they were exactly right to push back," he said.
Gingrich indicated, however, that Trump's decision didn't violate the emoluments clause of the Constitution. He claimed that George Washington, who helped craft the clause, ran Mount Vernon while serving in office.