Maryland is among the most Democratic of states, with a solid blue streak in presidential elections all the way back to 1992.

With Sens. Barack Obama and Hillary Rodham Clinton waging the tightest Democratic race in decades, it's no surprise that Tuesday's primary will be the most important here since Jerry Brown beat Jimmy Carter in 1976.

But Maryland's Republican primary will matter even more.

That's the latest, unexpected consequence of the decision by state Democratic leaders to advance the primary to Feb. 12, when Maryland, Virginia and the District of Columbia will have the national spotlight to themselves.

Even Democratic insiders acknowledge that Maryland voters are likely to have a more consequential impact on the Republican nomination.

"Before yesterday, I would have said it would have meant more to the Democrats," said Terry Lierman, a former state Democratic chairman and a prime mover behind the creation of the "Potomac Primary" (or "Chesapeake Primary," as some are calling it.)

Super Tuesday changed the equation overnight, after Mike Huckabee's primary victories in the South killed John McCain's hope of being crowned his party's presumptive nominee this week.

Suddenly, there is an added premium on winning Tuesday's Republican vote, as McCain scrambles to secure the delegates he needs to clinch the nomination.

Yesterday morning, he sought to assure Republicans that he's taking nothing for granted, despite a seemingly insurmountable lead in delegates. In a tacit acknowledgment of the changing dynamics of the race, McCain shook up his travel schedule. He's expected to be cruising Maryland highways on his campaign bus soon, perhaps as early as this weekend.

"We've got to try to wrap this thing up as quickly as possible," he told reporters in Arizona. "So we'll be hitting the campaign trail tomorrow morning."

McCain had planned to be in Europe this weekend. The idea was to turn an international military conference in Germany into a showcase for his campaign, holding face-to-face talks with top foreign leaders and projecting the winning image of a would-be president.

Mitt Romney, a distant second in the delegate count, plans to speak tonight in Baltimore County, as the remaining Republican contenders recalibrate their strategies. Mike Huckabee is expected to target Virginia, which could be McCain's biggest headache on Tuesday.

The shores of the Chesapeake and Potomac provide a lode of Republican delegates - 116 - and party rules make it possible for one candidate to collect them all.

McCain already has almost three times as many delegates as his nearest competitor and, by some counts, is less than 400 away from clinching the nomination. A sweep on Tuesday would make it virtually impossible for anyone to stop him.

McCain is heavily favored in Maryland, though neither he nor his opponents have done much to organize the state, according to Republican politicians.

Clinton and Obama, meanwhile, have yet to announce specific plans, though both are expected to make appearances in Maryland.

One thing is known: The Potomac Primary won't really resolve anything on the Democratic side.

The dead-even nomination fight is turning into a grinding effort to pick up delegates one at a time - a process likely to stretch into the summer.

Obama is favored to win all three Potomac Primaries. But a sweep would not generate a delegate landslide, since party rules make it possible for the loser to get almost as many delegates as the winner.

With a total of 168 Democratic delegates at stake, "we think over the course of the Chesapeake Primary, the delegate margin overall would be within 15 delegates," said Guy Cecil, the Clinton campaign's national field director.

If that seems like a minuscule haul, consider this: On the biggest primary day ever, with 1,681 delegates up for grabs, the apparent result, almost incredibly, was a near-perfect split.

With the delegate counting still incomplete, Obama's campaign projected that he wound up winning five more delegates than she did. Clinton's camp said, no, she got one more delegate than he did. Either way, it was a wash that left Clinton where she was before Super Tuesday, with a lead of about 80 delegates.

Tuesday's Democratic vote should help Obama chip away at that advantage, but this month's remaining primaries and caucuses will serve mainly as a bridge to the next big showdown, on March 4 in Ohio and Texas, where Clinton is the early favorite.

"This is going to be a neck-and-neck contest for the foreseeable future," said Howard Wolfson, the Clinton campaign communications director.

He said Democrats could be looking at a race that doesn't end until the week before Labor Day, at the nominating convention in Denver.

paul.west@baltsun.com