Scott Brown’s career on the national stage has been a study in contradictions. He is a Northeast Republican with a working class, rather than coastal elite, political identity. He won Ted Kennedy’s Senate seat when the late senator passed away by running against the health-care reform effort that was associated with Kennedy perhaps more than any other politician aside from President Obama. He then accrued broad popularity and high approval ratings, yet lost his reelection bid anyway.

Out of office, the contradictions continued: he declined to run for Massachusetts’s other Senate seat when it opened up, and so he was a popular and skilled politician without office–a gifted campaigner without a campaign to run. Yet passing on the other Senate seat still made some sense, because he could run for governor of Massachusetts instead. That election would likely pit him against less formidable competition for an office to which Bay State Republicans get elected routinely, unlike the Senate. And it would offer him a chance to raise his national profile, in the event that he, like most politicians, was looking downfield.

But then he passed up the gubernatorial election as well. What gives? Perhaps, some wondered, he was actually considering running for the Senate from neighboring New Hampshire. The Granite State is more hospitable for Republicans than Massachusetts, and it would be a boon to any national aspirations he had because Republican support in New Hampshire is not the anomaly it is in Massachusetts. Now, it seems, Brown has taken another step in that direction:

Former US senator Scott Brown will headline the New Hampshire GOP holiday dinner this month, furthering speculation that he is considering a run for the Senate in that state. …

Brown himself has remained coy about his plans. He has changed his Twitter handle from @ScottBrownMA to @SenScottBrown.

Would Brown be viewed too much as a carpetbagger to win in New Hampshire? It’s an interesting question, because it would test the extent to which regionalism can trump localism in Northeastern politics. By that I mean: we are constantly being told that Northeast Republican candidates for national office (usually the presidency) can offset their lack of ideological bona fides by competing for states Republicans don’t usually win during presidential elections.

Mitt Romney was an example of this. No, the thinking went, he can’t win Massachusetts, but maybe he can win New Hampshire. In the end, he could not win New Hampshire, but the idea was only on the table because he hailed from a nearby state. Rarely do we speak of regionalism this way for other areas of the country. It’s true that there is something to being a southerner, but much of that is tangled up in liberals’ evergreen amateurish smears that Republican success in the South means they must be racist. And anyway “the South” is a bit amorphous and far more diverse than it is given credit for, making regionalism a tough sell.

At other times, race and ethnicity do play into regional assessments, but in a more positive way. Republicans may speak of success in the Southwest, for example, in terms of outreach to Hispanic voters instead of, say, being from Phoenix. But the Northeast continues, against all odds, to play this siren song on a loop. In many ways, a Scott Brown Senate run from New Hampshire would be an even better test of this theory than a presidential contest, because it would put state issues front and center and really assess their portability.

But it turns out that were Brown to run in New Hampshire, he might preempt this test by injecting national issues into the race, indicating the limitations of Northeast regionalism. The issue Brown is most likely to raise would be the one that played a role in his initial Massachusetts win: ObamaCare. As the Washington Post reports:

In the FoxNews.com op-ed, Brown focuses on the effects of the federal health-care law in New Hampshire — not Massachusetts, notably — and appears to take a shot at his would-be opponent, Sen. Jeanne Shaheen (D-N.H.).

“Many other Americans are experiencing fewer medical options as insurers restrict their choice of doctors and hospitals in order to keep costs low,” Brown writes, adding: “For example, in New Hampshire, only 16 of the state’s 26 hospitals are available on the federal exchange, meaning patients must either pay more to keep their current doctor or seek inferior care elsewhere.”

Brown then mentions New Hampshire a second time: “New Hampshire is not alone. Across the country, some of the best hospitals are not available on plans on the exchange, leaving patients with difficult choices and unwanted sometimes, life threatening decisions.”

The irony here is that nationalizing issues was something his Massachusetts opponent, Elizabeth Warren, used against him in her successful bid to turn him out of office. Warren herself was a transplant to Massachusetts, though she arrived in the state long before she had senatorial ambitions. If New Hampshire’s voters dislike ObamaCare enough, they’d probably be open to an out-of-stater who promises to help unburden them. That appears to be Brown’s bet–if he runs, something he has made a steady habit of avoiding so far.