The Collins campaign has defended the ad.

[Mr. Collins had suspended his campaign after being indicted, but he resumed his re-election effort last week.]

“This is a real video of Nate McMurray that he removed from social media because he didn’t want to defend his efforts to promote a Korean-U.S. Free Trade Agreement that shipped nearly 100,000 U.S. jobs overseas,” Natalie Baldassarre, a spokeswoman for Mr. Collins’s campaign, said in a statement. “Nate McMurray needs a new video to explain why he opposes President Trump’s policies that are protecting American jobs and American workers. Hopefully, he’ll leave that video up.”

Mr. McMurray said the video was taken down after the summit because he was disappointed with Mr. Trump’s celebratory reception of Mr. Kim. Though he supported Mr. Trump’s overtures to Mr. Kim, Mr. McMurray said he was disappointed in the execution of the summit.

“It was a slap in the face to freedom,” he said.

The United States–Korea Free Trade Agreement passed Congress in 2011 with bipartisan support, but Mr. Trump has rallied against it. In his speech at the Republican National Convention, he called the agreement a “job-killing trade deal.”

Mr. McMurray said the video made no mention of the trade agreement, and his only involvement with the trade deal related to his work as a business consultant. Part of his job was to explain the impact of the agreement for businesses operating in Asia.

Had the Collins campaign “really cared” about the trade agreement, Mr. McMurray said, “they would have talked about it” in the ad.

“They didn’t,” he said. “This is a complete pivot because they’re embarrassed about what their real intention was.”