But Pagliuca, a co-owner of the Boston Celtics and a Democrat, said he knew something that others didn’t. When he golfed with Trump at a Boston-area course some years ago, Trump had talked at length about how much he admired Bain Capital, a private equity firm that Romney led until 1999.

Today, as Pagliuca and other Romney backers see it, Trump, 70, and the 69-year-old Romney had far more in common than many realize: Both came to prominence as risk takers and dealmakers, and both have spent much of their lives seeking to emulate and outdo the success of their fathers. Trump’s father, Fred, was a New York City developer, and Romney’s father, George, was a governor of Michigan who unsuccessfully sought the presidency…

“I would describe a potential relationship as complementary,” said Marc Wolpow, who worked with Romney at Bain Capital from 1990 to 1999 and also has met Trump. “I think if you would merge both of them you’d have the perfect president. . . . Mitt could be the good cop to the bad cops that surround Trump.”

Wolpow said the two men probably see qualities in the other that each is missing. Romney, he said, failed to connect with blue-collar voters and made “excuses” for his wealth, but he possesses the diplomatic skills to be secretary of state. Trump hit it off with many average voters and cited his financial fortune as part of his appeal, but his brusque manner could be problematic in handling world affairs.