Boston ? So it continues.

Mitt Romney’s daily-double followed Rick Santorum’s trifecta, and now the contest moves here to Massachusetts and to nine other states that together, in a Super Tuesday rush for delegates, probably won’t resolve the Republican presidential race any more than the last two rounds did.

But just because the race isn’t resolved doesn’t mean it isn’t clarified. In the muddle, some things are clearer than ever.

One is that there will be a lengthy Republican race. Another is that the Republicans have class divisions that mirror the ones the Democrats have been contending with for two generations. A third is that the party best positioned in a quarter-century to recapture the White House is itself so divided that a weak president grows in strength day by day.

This will be a Super Tuesday like few others. The term arose after Southern Democrats, impatient with the leftward drift of a party that seemed congenitally unable to win a national election, clustered the primaries of the Old Confederacy so as to create a regional battle that would work to the advantage of a moderate, business-oriented candidate.

But this is a contest of an entirely different character, mixing the old industrial heartland (and agricultural bounty) of Ohio with the high-tech suburbs of Massachusetts, the granola reaches of Vermont’s Northeast Kingdom, the energy environs of North Dakota and Oklahoma and the country-music ballad lands of Tennessee, Virginia and Georgia. Each of the contenders has a stronghold to defend and dangerous territory to explore.

As they do so — as they speed from Idaho to the South, and then gird for the ground war in Ohio — these questions grow in importance:

l What value do Republicans place on party unity?

On the surface, that question focuses on the fissures that two months of hard campaigning have laid bare: between conservatives and moderates, between those who oppose big government and those who aim more at big business, between candidates who play down religion and those who emphasize it.

The Michigan exit polls by Edison Research make these divisions clear. Romney prevailed among those who said they considered themselves somewhat conservative or moderate to liberal; Santorum was the clear winner among those who said they were conservative. Romney showed strength among those with incomes over $100,000, Santorum with those far less well-off. Voters who considered abortion the top issue went with Santorum; those who emphasized the budget and the economy with Romney.

But in some ways that is the least interesting, and surely the least surprising, element of the party unity question.

Santorum found himself in the middle of an illuminating contretemps last month when he admitted he “took one for the team” in supporting the No Child Left Behind legislation. Romney’s forces pilloried him for compromising, the very venal act that Santorum has accused his rival of performing repeatedly.

All this raises questions, unanswered by both men, of whether a candidate seeking to lead the country should be open to the sort of compromise that created the Constitution they would vow to protect and defend. That’s a debate worth having.

l Are the Republicans hurt by this ever-lengthening campaign?

The usual answer is that a long fight strengthens the eventual nominee, but this is not a usual campaign and there are signs this battle is not strengthening anybody but the president. The two principal candidates, plus Rep. Ron Paul and former House Speaker Newt Gingrich, are drifting rightward as the calendar turns, even though the conventional formula calls for candidates to drift toward the center as the general election nears.

It is a long time till November, though, and in 1960, when Richard M. Nixon won the nomination, the Republicans hadn’t even voted in their first primary until later this week. But Republican leaders are worried. They’d rather have a short, crisp race than a lengthy, messy one.

They will have to settle for the latter, and for the consequences. The Republican nominee will have to play the role of the king’s horses in Humpty Dumpty, though in this race hardly anyone is sitting on a wall.

Some Republicans worry they are reliving the 1964 Republican race, when Barry Goldwater lost 44 states. They ought to worry instead about whether they are replaying the 1968 Democratic race, when their rivals tore themselves up in the primaries and in a bloody convention and then lost a narrow contest.

l Might it come down to the Pennsylvania primary, and if it does, is Santorum sunk?

It might, and he probably isn’t. All the political pros know Santorum was routed in his 2006 re-election battle, losing Pennsylvania by 18 points. But that is a rare example of a meaningless truth.

Many Pennsylvania voters do have strong, negative feelings about Santorum, sometimes expressing them with unusual hostility. Almost none of those people will vote in the Republican primary April 24.

Santorum likely will be the strong favorite in Pennsylvania, though the state’s primary sets up as Santorum’s version of the Romney defensive play in Michigan. Just as Romney would have been seriously wounded had he lost Michigan, Santorum would be lunch meat if he loses Pennsylvania.

l Is Paul LePage right?

Paul LePage is the injury-prone governor of Maine, known for his attacks on a state labor mural and his willingness to tell the president of the United States to “go to hell.” But for all his stumbles, LePage may have stumbled on an inconvenient truth the other day when he suggested that the Republicans need a fresh face in the presidential race.

That is like saying that a hungry child needs a hearty meal. He may not get it — and the Republicans may not get that fresh face.

It is awfully late in the contest, even though it is only early March, and the Republicans are surfeited with reluctant warriors, the 21st-century versions of Thomas Paine’s summer soldiers and sunshine patriots. The remaining candidates have been saying of themselves: What you see is what you get. Increasingly it’s clear that they’re saying that of the Republican field as well.