Four years ago, Scott Brown kicked off a string of Republican victories nationwide by winning Ted Kennedy's Senate seat in a Massachusetts special election. He united moderates and Tea Party conservatives with a populist pitch for "the people's seat."

This year is also expected to be good for Republicans. But it will have to be really good, a GOP wave election, for Brown — two years removed from losing his Senate seat to Elizabeth Warren — to beat Democratic Sen. Jeanne Shaheen in New Hampshire.

A recent National Journal report described Brown's dilemma quite well. He's "down double digits in the polls, he's likely to be outspent by Sen. Jeanne Shaheen, and he's gotten headlines lately for all the wrong reasons — rebutting allegations that he hid from a reporter in a bathroom to avoid tough questioning."

From the people's seat to the toilet seat.

Brown was actually polling better against Warren in the final weeks of the 2012 campaign than he is against Shaheen right now. The Real Clear Politics polling average had him at 47 percent in the earlier race, just three points behind Warren, compared with 40.2 percent and a 10.4-point deficit today.

Meanwhile in Massachusetts, the Democrat Brown beat in that special Senate election seems poised to become the next governor. Attorney General Martha Coakley has steadily led Republican Charlie Baker throughout the campaign.

But with the exception of a recent CBS News/New York Times/YouGov poll, Coakley has rarely been above 50 percent. She showed some slippage in the Boston Globe's polling, with a 13-point lead in June dipping to 11 points, then nine points, then five points, then three — the last within the poll's margin of error, as she took just 39 percent of the vote.

Coakley is back up to a five-point lead in the latest Globe poll, but she's also winning just 38 percent of the vote in a Democratic stronghold. Nevertheless, she seems unlikely to blow a second "sure thing" election in four years, because Baker has yet to break 40 percent in any major poll.

The likeliest scenario is that Coakley will, like Deval Patrick in his 2010 re-election bid against Baker, cruise to an unimpressive win thanks to the Democratic makeup of the state electorate.

It's not hard to imagine an alternative scenario in which Coakley finds herself in quite a bit more trouble. What if Brown ran for governor of Massachusetts — the state where he lived most of his life and won 10 consecutive elections — instead of senator from New Hampshire? What if Coakley faced a rematch with Brown instead of a contest with Baker, a health-care executive?

In Massachusetts, Brown excelled at retail politics. Actually being from the Commonwealth certainly helped him in this regard. Seeming to be a more authentic product of the Boston suburbs was a huge plus in his race against Coakley, who was viewed as aloof and famously misidentified legendary Red Sox pitcher Curt Schilling as a "Yankees fan."

New Hampshire is a retail politics state with cultural and media ties to Massachusetts. As evidenced by Mitt Romney's strong showings in early Granite State presidential polls, being from Massachusetts isn't necessarily a political liability.

It should not need to be said, however, that Massachusetts and New Hampshire are different states. By switching states, Brown gave up one of his biggest political advantages. A second advantage — his nice-guy image — took a pounding in the tough Senate race against Warren.

Shaheen is an incumbent senator and former governor. She knows the state well and its voters are familiar with her. She has a history of winning crossover votes there.

Brown was my state senator when I lived in Massachusetts. He began his political career in the community next to my hometown. When he ran for Kennedy's Senate seat, I assumed he was setting himself up for a run for governor. It worked for Romney.

I was wrong. He is apparently so serious about being a senator that he is willing to tour New England in pursuit of a seat — even with a winnable governorship at home in Massachusetts.