Mitt’s a punching bag.

STRATHAM, N.H. (AP) — Just as Mitt Romney declared Thursday that he’s in, it’s suddenly looking like he’ll have more company in his campaign for the Republican presidential nomination.

While Romney made his candidacy official in New Hampshire, political heavyweights Sarah Palin and Rudy Giuliani caused a stir of their own with visits to the first-in-the-nation primary state.

…Romney oversaw a health care law enacted in Massachusetts that’s similar to Obama’s national health overhaul, which conservatives despise.

“If I ran through all my mistakes, Ann would love it and you’d be here all night,” Romney said, referencing his wife but not explicitly acknowledging the hurdle while calling for a repeal of Democrats’ national plan.

His rivals weren’t about to let it go. Asked about how big a problem Romney faces regarding the Massachusetts health care law, Giuliani was critical.

“The reality is that Obamacare and Romneycare are almost exactly the same,” former New York Mayor Rudy Giuliani said in New Hampshire today. “It’s not very helpful trying to distinguish them. I would think the best way to handle it is to say, it was a terrible mistake and if I could do it over again, I wouldn’t do it.”