Scott Brown was one of the great GOP Senate upsets, beating Democrat Martha Coakley in 2010 to fill the Massachusetts seat of the late Ted Kennedy — only to be defeated in November 2012 by Elizabeth Warren.

Now, Brown is plotting a return to the upper chamber — in a different state.

Brown, who owns a home in New Hampshire, launched his exploratory committee today to challenge Sen. Jeanne Shaheen (D-N.H.) this fall.

“It wasn’t so long ago that the Democratic establishment in Washington was feeling very comfortable, like they just couldn’t lose. You could tell they were comfortable because they kept shoving Obamacare at us, and didn’t much care how the American people felt about it. Well, Election Day is still eight months away, and they’re already in panic mode. A big political wave is about to break in America, and the Obamacare Democrats are on the wrong side of it,” Brown said in an address to the Northeast Republican Leadership Conference.

“The Democratic leadership likes to say that Obamacare is the law because elections have consequences.  But false promises have consequences too.  And the party that put everything on the line for that takeover of healthcare is going to have a lot to answer for,” he continued, adding that tens of thousands of residents in the state have lost their health insurance plans.

“…There’s only one way to get rid of Obamacare once and for all, and that is to get rid of the Obamacare Democrats who rammed it through Congress and forced it upon the American people.  Whether it’s Nancy Pelosi saying we have to pass the bill to see what’s in it, or the go-along senators who vote 99 or 100 percent with Obama – it is time for that whole crowd to go.”

Brown tried to brush off carpetbagger criticism by talking about his childhood years in New Hampshire. “During my challenging early years, one influence that made all the difference for me was the care of my grandparents. And I think of them often these days, because so much of the time we spent together was here in New Hampshire,” he said.

Shaheen faced no formidable GOP opponent, but Brown could put the seat into play for Republicans. This decision and Rep. Cory Gardner’s (R-Colo.) recent announcement that he’ll challenge Sen. Mark Udall (D-Colo.) are both music to the ears of GOP strategists.

What else has Brown been up to since leaving the Senate? Making trips to Iowa — fueling speculation that he’s also thinking 2016.