"The feature of the Trump campaign that they have consistently been telling everybody is an asset is that they are a small, nimble unit that doesn't require layers of bureaucracy and thousands of staffers," McKinnon told David Axelrod on "The Axe Files" podcast, produced by CNN and the University of Chicago Institute of Politics. "They're getting payback for that because when you do a national speech on television, the one absolute obligation and responsibility the campaign has is to vet that speech."
Speaking on Tuesday, McKinnon said the story had robbed Trump of early momentum in the convention week.
"This (convention) is a four-day window of opportunity and they just erased one of them. They just took one day and threw it out the window, in terms of controlling their message, and it's spiraled completely out of control."
On Wednesday Meredith McIver took responsibility for using passages from a 2008 Michelle Obama speech after Melania Trump read her some passages from that speech.
"I wrote them down and later included some of the phrasing in the draft that ultimately became the final speech," said McIver, whose offer to resign was declined by Donald Trump.
But McKinnon says it is the campaign's responsibility to check the speech before it's delivered.
During the conversation with Axelrod, McKinnon, the co-creator, co-executive producer, and co-host of Showtime's "The Circus: Inside the Greatest Political Show on Earth," said the GOP's failures to make inroads with Hispanic voters in the past decade has left the party in a precarious position.
"We're clawing our way to the bottom with Hispanics," he said.
According to a recent Wall Street Journal/NBC poll, Trump only has the support of 14 percent of Hispanics, compared to 76 percent for Hillary Clinton, and that, McKinnon believes, means Trump faces a huge challenge to make up the gap with white voters.
"It's hard to see it on paper. It's really hard to see it," he said. "I mean, and even if you do, boy... for the sake of the Republican Party, and the sake of our country, you know, I hope we don't have a President that is simply elected with one demographic constituency."
To hear the whole conversation with McKinnon, which also touched on his work in political advertising early in his career, his switch from the Democratic to the Republican Party, his close personal and professional relationship with former President George W. Bush, and much more, click on http://podcast.cnn.com
. To get "The Axe Files" podcast every week, subscribe at http://itunes.com/theaxefiles