Bush has stopped short of directly confronting Christie by holding a fundraiser on his home turf. But behind the scenes, he has been quietly wooing, via e-mail, a cadre of high-profile Christie backers, including a group that attended a private dinner with Bush at New York’s Union League Club in January.

“I’ve known and admired Jeb for many years and I’m obviously intrigued by his candidacy, or I wouldn’t have had dinner or communicated with him in recent weeks,” said New Jersey State Sen. Joseph M. Kyrillos Jr. (R), who chaired Christie’s 2009 gubernatorial campaign and attended the New York dinner. “Time will tell how things evolve.”

New York Jets owner Woody Johnson, a onetime Christie booster, signaled his support for Bush on Wednesday when he showed up at a fundraiser in Chicago for Bush’s political committees.