For a Beltway outsider, Mitt Romney amassed a slew of K Street heavy hitters. Now that the former Massachusetts governor has ended his presidential campaign effort, those lobbyists are feeling the sting of backing a losing candidate — while also having to decide where to throw their support.

Although it’s always a risk for lobbyists to pick a favorite primary contender, many do because of personal connections, client interests or political ties.

Romney’s K Street supporters included veteran party insiders

like former Rep. Vin Weber (R-Minn.) at Clark & Weinstock, Dutko Worldwide’s Ron Kaufman and Blank Rome’s David Norcross, both of whom have longstanding ties with the Republican National Committee.

While most lobbyists who had backed Romney said they will shift their loyalty to Sen. John McCain (R-Ariz.), their party’s presumptive nominee, a small minority said McCain will never get their vote. Some observers also speculate that the bitterness between the McCain and Romney camps could spill over into the lobbying business.

“The risk for a lobbyist is that a Member’s office, and particularly the staff, track which lobbyist is supporting which candidate and then go out of their way to not be helpful to that lobbyist’s clients,” said one lobbyist who would not be quoted by name. “I know of several staffers, independent of their Members, who are keeping track of who’s backing who on both sides of the aisle and will do whatever it takes not to be helpful to those lobbyists and their clients.”

Perhaps no one on K Street was a bigger champion of Romney’s run than Kaufman, chairman of Dutko’s executive committee. Several of Kaufman’s Dutko colleagues also got behind Romney, leading some K Streeters to wonder quietly if the firm’s lobbyists or clients will face any bitterness from McCain supporters.

“I’ve never worried about that,” said Kaufman, who volunteered in Iowa, New Hampshire, Michigan and Florida for Romney’s campaign. “What I do as an individual, I do as an individual. The reason people get involved in politics is to try to make a difference.”

Kaufman, a Massachusetts native, said he was won over by Romney more than three years ago — after having backed Romney’s unsuccessful primary opponent, John Lakian, in the Bay State’s 1994 Republican Senate race. (Romney subsequently lost to Democratic Sen. Edward Kennedy.)

“Mitt’s a friend,” said Kaufman, who planned to take some rest and relaxation after Romney suspended his bid. “Of course I’ll support the nominee,” he added. “Mitt said it exactly right — the most important problem facing this world today is jihadism, the threat of terror. I disagree with Sen. McCain on some issues, but it’s the one issue where he is absolutely right.”

Romney ran a close third among GOP candidates to former contender Rudy Giuliani in campaign contributions from lobbyists, taking in $255,175, according to the most recent data compiled by the nonpartisan Center for Responsive Politics. Frontrunner McCain has collected the most from lobbyists, $416,321, while Giuliani reported $270,525.

And while many who only heard Romney in the impersonal settings of the campaign trail thought his appearance stiff and language cliched, lobbyists who met him in person said that in intimate settings, Romney showed he had a command of health care, economic and tax issues.

“He’s much better in small groups,” said one lobbyist who supported Romney. “When he’s on stage, he looks like his hair’s too perfect. You get him to put his feet up and … I was pretty impressed.”

For many younger lobbyists, Romney was also an attractive candidate, and one whose inner circle was not yet closed off to newcomers.

“If you weren’t part of McCain’s inner circle, you weren’t going to get close to the guy,” said one Republican lobbyist who did not support Romney. “Of all the candidates, Romney was definitely the most accessible for the average lobbyist.”

Drew Maloney, a lobbyist with Ogilvy Government Relations, was an early supporter of Romney and served as co-chairman of the Young Professionals for Mitt program.

“He had a strong appeal to me personally,” Maloney said. “The fact that he’s run a business, managed a state and fixed the Olympics — that business savvy was very appealing to me.”

Maloney and the other nearly 400 young professionals helped organize events and fundraisers in Washington, D.C., and other cities. He also helped the Romney campaign target potential supporters on Capitol Hill. Maloney, who represents oil and gas companies, worked to put together an energy roundtable in Houston.

Maloney says his colleagues who back McCain already have reached out to him for his support. “At the end of the day, we’re all going to have to join together and help our candidate,” he said. “I’m a Republican, so I am going to help the ticket.”

Added Ed Kutler, a partner at Clark & Weinstock who previously supported Romney: “I’ve already put my credit card to good use toward McCain. The party wants to win in the fall, and Sen. McCain wants to win. I really do think these talks of division are overstated.”

Amy Flachbart, a government affairs adviser at K&L Gates, grew up in Massachusetts and after examining Romney’s record, she said, she signed on as an early supporter and participated in the Young Professionals for Mitt effort. “I’ve come to learn that Gov. Romney’s a man of strong principles,” she said.

And although she took personal time off from work to help the Romney campaign in New Hampshire before its primary last month, she says she will now support the party’s nominee.

Not all of Romney’s K Street supporters plan to take such a conciliatory approach.

One lobbyist who openly supported Romney for president said flatly, “I will never vote for John McCain.” While McCain has raised far more money from lobbyists than his competitors, many K Street Republicans say they dislike him because he has displayed a mean streak for their industry — in part by blasting appropriations earmarks and dragging now-jailed lobbyist Jack Abramoff and his associates before the Senate Committee on Indian Affairs, which he used to chair.

Others have concerns, but take a less heated approach.

Gregg Hartley, the chief operating officer of Cassidy & Associates and the former chief of staff to House Minority Whip Roy Blunt (R-Mo.), offered a glimpse into some of the skepticism about McCain.

“I don’t know John McCain personally,” Hartley said. “As a former House Republican, I have to give it some real thought because House Republicans like to think in terms of team concept.” And McCain, he said, hasn’t always been viewed by House GOPers as a team player. “I think there are a number of people who would like to get some comfort level that there’s going to be some transformation,” he said, adding, “I do believe it’s important that Republicans come together.”

Gary Schleuger, president of Pioneer Government Affairs and a Romney backer, said he believes Romney bowed out of the race so the Republican Party could coalesce around McCain. “I think most people will [do that], including myself,” he said.

But Schleuger said Romney’s announcement caught him and other volunteers off-guard. He was in the midst of organizing phone banks and getting literature ready to go door-to-door on Romney’s behalf in Virginia, which has a primary on Tuesday. “We were ramping up as of late last night,” Schleuger said on Thursday, the day of Romney’s announcement.

Norcross, a former general counsel to the Republican National Committee, said that initially he had no intention of backing Romney, but after meeting the former governor at two small events, he decided Romney was the right person for the job. Norcross tapped his considerable fundraising network to help Romney’s coffers and lobbied for the support of fellow RNCers.

“We ended up with more RNC members endorsing Gov. Romney than all other candidates together,” Norcross said.

As for what he will do next, Norcross, just hours after Romney’s announcement said, “I don’t know.”