GOFFSTOWN, N.H. — Mitt Romney gave supporters here advice today on how to defend his candidacy against critics who call him a flip-flopper, spinning the issue into a sales pitch for his private sector experience.

“How do I fight these people?” a Romney supporter asked the former Massachusetts governor.

“Let me give you some brass knuckles, that will help,” Romney quipped during his town hall at the New Hampshire Institute of Politics at St. Anselm College.

Romney added that he doesn’t “whine” about being called a flip-flopper — New Hampshire Democrats mounted a stunt involving flip-flop shoes to welcome the Republican to the Granite State — because he knows being in politics can get “pretty rough and tumble.”

Then he offered what’s become a standard line of defense when he is charged with being on both sides of President Barack Obama’s health care law, gay rights and economic issues.