Former Massachusetts Sen. Scott Brown is making all the right moves for someone looking to make another Senate run. This time, however, the seat Brown might seek is in neighboring New Hampshire.

Brown, who lost a re-election bid in Massachusetts in 2012, has over the past few weeks become markedly more receptive to the idea of challenging Democratic Sen. Jeanne Shaheen, of New Hampshire, and sources close to the Brown say the odds of him running have risen to 50-50.

“He's certainly leaving the option open, whereas he's closed the door on other races,” including a special Senate election in Massachusetts to fill the seat vacated by Secretary of State John Kerry, and a bid for Massachusetts governor, said one strategist familiar with Brown's thinking. “The only door he's leaving open is New Hampshire Senate.”

Brown is in no hurry to make a decision before the New Year, but he has been dropping public hints that he's interested. Last month, he erased the "MA" (for Massachusetts) from his Twitter handle, which is now just @SenScottBrown. He established a political action committee in New Hampshire that made a $10,000 contribution to the state GOP. And on Dec. 19, he'll headline a New Hampshire state Republican holiday reception.

Were Brown to enter the race, he would likely command extensive media attention, raise a considerable amount of campaign cash and present a formidable challenge to Shaheen in the general election. A Public Policy Polling survey in September showed Shaheen leading Brown by just 4 percentage points, 48 percent to 44 percent.

Still, the decision to run for the Senate in New Hampshire is not an obvious one for Brown, who is said to enjoy his private-sector job at a law firm since losing to Democrat Elizabeth Warren last year. For a time, there was also a chance two other New Hampshire Republicans -- Rep. Charles Bass or former Rep. Jeb Bradley -- would run as well, and Brown likely would not have challenged either. But both men opted out of the race, and Bass recently told National Journal that he has urged Brown to run.

During a 16-day government shutdown in October, Brown was hesitant about a return to public service. But the sloppy rollout of President Obama's signature health care law has caused him to reconsider. He senses a political opportunity to be seized, allies say. Brown on Tuesday published an op-ed for Fox News that criticized the health care law and made specific mention of New Hampshire.

Sen. Jerry Moran, R-Kan., who leads the National Republican Senatorial Committee, told the Boston Globe last month that the committee wants to recruit Brown to run. New Hampshire political activists just hope Brown will decide soon to reduce uncertainty for the rest of potential GOP field ahead of the September 2014 GOP primary.

New Hampshire Republicans insist Brown would be welcomed into the race, despite his being from Massachusetts.

“We have a tradition up here of giving all candidates a fair shot,” said New Hampshire GOP Chairwoman Jennifer Horn. “As the senator has spent more and more time up here, the feedback I’ve gotten from the grassroots has been overwhelmingly positive.”

Brown will soon be spending much more time in New Hampshire. He is in the process of selling his home in Wrentham, Mass., with plans to move to his vacation home in Rye, N.H.

Brown’s allies and national Republicans were concerned that Brown could be labeled as a “carpetbagger” for state-hopping, but those fears faded somewhat lately when former New Hampshire Sen. Bob Smith, a fellow Republican who spent the last decade living in Florida, announced that he was entering the race.

So far, national Democrats brush off the notion of a resurgent Brown and remain skeptical that he would run for Senate in New Hampshire. Either way, they say, they’re confident in Shaheen’s re-election outlook.

“Jeanne Shaheen is an incredibly strong candidate who is well-liked in New Hampshire and has a strong financial and organizational head start over any potential GOP nominee,” said Democratic Senatorial Campaign Committee spokesperson Justin Barasky.

National Republicans are optimistic about Brown's general-election chances should he run, even to the point of waxing poetic. When asked about Brown's potential candidacy, one Republican operative pointed out that Shaheen sits at the Senate desk that once belonged to former Sen. Daniel Webster, a Whig lawmaker during the 19th century who, before he represented Massachusetts in the Senate, was a member of Congress from New Hampshire.