BALTIMORE — Some influential House Republicans voiced concerns Friday about a prolonged primary fight for the GOP’s presidential nomination, warning that it could prove divisive and turn into a battle on personal issues that distract from the party’s economic message.

“The more we can coalesce around a single vision with the nominee, I think the more straightforward the choice is going to be for the electorate. It’s the issues that need to be decided by this election,” House Majority Leader Eric I. Cantor (R-Va.) said in an interview at the Republican conference’s three-day policy retreat. “I think it behooves us all as a country to have sort of the choice laid out as early as possible so we can begin in earnest the discussion about the issues.”

Cantor, who has not endorsed anyone in the race, suggested for the first time that he might do so. While he gave no indication of his leanings, he is a close ally of Virginia Gov. Robert McDonnell, who endorsed former Massachusetts governor Mitt Romney on Friday morning.

Regardless of who the nominee is, Cantor said a key focus of the three-day gathering in Charm City has been planning ahead to sync up the House GOP agenda with the nominee.

Some of the 89 freshmen are drifting toward supporting Romney and looking for a swift conclusion. “I think there’s a growing acknowledgment that Mitt Romney’s the person,” said freshman Rep. Cory Gardner (R-Colo.). While he has yet to endorse in the race, Gardner said he worried about the other candidates’ ability to appeal to swing voters. “Romney’s the candidate who can carry Colorado,” he said.

Supporters of former House speaker Newt Gingrich, however, are moving swiftly to try to find new endorsements as his campaign appears on the rise ahead of Saturday’s primary in South Carolina. With Texas Gov. Rick Perry abandoning the GOP race Thursday, a dozen House Republicans are now free to back a new presidential contender. Gingrich’s supporters here in Baltimore have had informal discussions with other Republicans, arguing that the former speaker is the one true conservative left in the race who can defeat Romney.

The Gingrich camp plans to move quickly if he can prevail Saturday. “They’re going to hold their powder dry to see what happens in South Carolina,” said Rep. Joe Barton (R-Texas), the first congressman to endorse Gingrich last year. “If good things happen in South Carolina, I think you’ll see some of the Texans come on board next week.”

Most of Perry’s previous support came from within the massive Texas delegation.

By the end of this week, Romney had the backing of 72 members of Congress; Gingrich just 11, according to a tally maintained by Roll Call.

Barton, who served with Gingrich for 18 years in the House, said the former speaker was happy to continue playing the role of anti-establishment conservative, but he wanted to demonstrate momentum through more congressional endorsements as well institutional support for “legs on the ground” as the primaries move into bigger states across the country. If Gingrich can stay in the race long enough to make it a one-on-one battle with Romney, his camp believes more support will flow his way.

“Fairly quickly, it will be a Newt-Romney race. I think Newt wins that,” Barton said.

Romney’s camp has made the counter-argument to their undecided colleagues: that Gingrich is the most unreliable of the potential nominees and that wrapping up the nomination as soon as possible is best for the entire party.

“Most are getting close to recognizing Romney’s the one that can best take on Obama successfully,” Rep. Cathy McMorris Rodgers (R-Wash.), a Romney supporter, said Friday.