Is Republican gubernatorial nominee Mitt Romney facing trouble in Boston? The Boston City Committee, the city branch of the state Republican Party, met Tuesday night and endorsed Jim Rappaport for lieutenant governor, snubbing Kerry Murphy Healey, Romney’s anointed running mate.

" Mitt doesn’t understand. Mitt is a businessman, " says Bill Mallard, chair of the Republican Party in Boston, of Romney’s decision to pick his own running mate. " He’s not even elected and he’s saying, ‘Jump,’ and people are saying, ‘Hey, you’re not in office yet.’ " Mallard threatened trouble if Rappaport wins the number-two slot and Romney fails to treat him properly. " If Jim isn’t a co-equal, we’ll take a pass, " he says. " We won’t work on [Romney’s] election. "

Acrimony among the state’s GOP grassroots has been an unpleasant side effect of Romney’s decision to campaign with Healey, while simultaneously letting it be known that he does not want to work with Rappaport. But it could have been predicted. Rappaport has worked zealously for months to capture the support of rank-and-file Republican activists, in many cases calling them individually. This paid off at the Republican convention in April, when the rank and file nominated Rappaport even as Romney tried to swing support Healey’s way.

In Massachusetts, GOP politics has a long history of fierce tension between candidates who play to the Republican " grassroots " and those who play to the broader electorate. Activists lament that successful Bay State Republicans, such as former governors William Weld and Paul Cellucci, do what they need to do to survive within the GOP but essentially ignore the party apparatus, a practice that helps individual candidates but keeps the party weak and, by extension, makes Massachusetts a one-party (Democratic) state. (That said, the strategy makes sense. Statewide Republican candidates do this because most die-hard Republicans, who represent only 13 percent of state voters at best, are far to the right of the general electorate.)

But don’t tell that to Mallard, who’s also angry with Romney’s advisers — particularly media consultant Michael Murphy, who, Mallard says, has encouraged Romney to ignore the state GOP rank and file. " He’s being manipulated by people from other states, " says Mallard. " The [local] people best know how to run local campaigns. " (Interestingly, problems with Republican grassroots activists also beset New York congressman Rick Lazio in his 2000 Senate battle with Hillary Rodham Clinton — a race in which Murphy also played a prominent role.) In any event, if Rappaport wins the primary, how Romney manages their relationship will be one of the most interesting aspects of the general election.