For Romney, Secret Service Detail Poses Challenges on the Campaign Trail LAS VEGAS - Looking back on elections past, every campaign has a handful of true pivot points - Barack Obama's race speech in 2008, or John McCain's choice of running-mate. But one symbolic juncture comes when a challenger gets assigned his or her Secret Service detail. For Mitt Romney, it happened on Thursday. This moment is always a turning point for a campaign. The appearance of a team of dark-suited, ramrod straight, hyperprofessional-looking agents means that a candidate has made it big time, with all the ensuing trappings and expectations. But there is downside as well as upside, and the campaign has to be sure to manage the potential ramifications carefully. The most important side effect will be on Mr. Romney's interaction with supporters, whose access to the candidate at events is likely to be inversely proportional to the number of agents assigned to him. Someone briefed on the matter said that there are currently seven agents assigned to Mr. Romney's detail, not all of whom will necessarily travel with him, but that number will probably ramp up as his campaign grows. Reid Cherlin, a GQ contributor who is covering the Republican primaries, worked on both President Obama's campaign and in his White House, and said that having a Secret Service detail "complicates things" for everyone involved. "Especially in retail-focused states, all of a sudden roads are closed, there are traffic jams, people can't get close to the candidate, the local press feels mishandled," he said. "So there you are cruising down a two-lane blacktop in a tiny town at 80 miles per hour in these black S.U.V."s. It can be a fun spectacle in a bigger city, but in tiny towns where people want to meet the candidate, it can be a problem. "It can create sort of P.R. challenge," he added. Suddenly, grandmothers who simply want their book signed might be accidentally jostled, and local donors cannot always be taken backstage to meet the candidate. People will have to be screened - often passing through a magnetometer - in order to enter campaign events, creating yet another layer of hassle and frustration for potential supporters along with enhanced safety and isolation for the candidate. The moment on Wednesday when Mr. Romney was glitter-bombed - protestors showered him with cans full of glitter as he took the stage in Minnesota - might never have happened with Secret Service on the job. The press feels the Secret Service's presence, as well. In the summer, when Mr. Romney's campaign was still fresh, it was possible to walk directly up to him, so close you could tap him on the shoulder. As the crowds grew, the press got pushed further back, but you could still worm your way close enough to hear Mr. Romney's intimate interactions with voters. For a politician like Mr. Romney, who is remarkably disciplined in public and rarely mixes up his stump speech, those moments on the rope line offer brief glimpses into an impromptu and unscripted version of the candidate. It was on the rope line that we learned about his penchant for guessing voters" ages and heritage - often incorrectly - and it was there that a reporter spotted Mr. Romney hand a wad of cash to an unemployed woman he felt bad for. All of those moments will become more difficult to see and hear as the security buffer around him expands. No one knows yet what Mr. Romney's Secret Service code name is, but a few weeks ago over a long dinner, his traveling press corps came up with their own suggestions. The Secret Service chooses a letter of the alphabet and then assigns the candidate and each member of his or her family a name from the same letter. The reporters went with "S." Mr. Romney's wife, Ann, who is known as the "Mitt-stabilizer" for her abilities to calm her husband, was "Serenity." His oldest son, Tagg, was "Scion." Ben, his doctor son was "Scalpel." And Mr. Romney himself was named in homage to his campaign theme song, Kid Rock's "Born Free," which includes the verse, "Wild, like an untamed stallion." Mr. Romney, at least to his traveling press corps, will always be "Stallion."