Republicans in Maryland have been ruled by Democrats for almost two centuries. They have been divided into gerrymandered districts that dilute their ability to elect members to Congress. And their disorganized ranks have left the party’s most extreme members with an outsize voice in state politics.

But on Tuesday, the often overlooked and bulging moderate middle of the Maryland GOP will be relevant — at least for a day. In the state’s first competitive presidential primary in a generation, polls and interviews suggest an overwhelming number of Republicans will vote for Mitt Romney.

They won’t be voting for the Romney they’ve seen tacking increasingly to the right to secure the party’s nomination. They say they’ll be voting for the Romney they see as a fiscal conservative — but someone who is also capable of compromise and nuanced positions and could beat President Obama: the post-Etch a Sketch Romney they suspect exists under a hardened coat of party rhetoric.

“There are more of us in this state than in others, I think, that are fiscally conservative and socially libertarian,” said state Sen. Allan H. Kittleman. The Howard County Republican, who backs Romney, was forced to step down as Senate minority leader after he introduced a bill last year allowing civil unions for Maryland gay couples. “Many Republicans here are concerned about some of the stands that senator [Rick] Santorum has taken or been advocating for . . . focusing more on social issues than economic ones.”

Social issues are not the central worry of the businesspeople, military veterans, contractors and like-minded government workers who make up the majority of Republicans in Washington’s Maryland suburbs.

They worry first about federal spending and debt, pruning government programs without choking off their livelihoods or the region’s economy. Many say they also are looking for a conservative who could break the gridlock in Washington.

For that, Romney holds another appeal. Having been elected to the top job in Massachusetts, a state only a shade bluer than their own, Romney is a lot like the guy Maryland Republicans were last able to elect to statewide office, former governor Robert L. Ehr­lich Jr.

“Obviously, we both represented blue states, we’re both acclimated to hostile legislatures,” said Ehrlich, Romney’s state campaign chairman. “Over the years, we’ve had several of those talks; we’ve traded war stories.”

Romney is leading Santorum, the former senator from Pennsylvania, by 17 percentage points, according to one recent poll. Ehr­lich and other Romney supporters think the final tally for the state’s 37 convention delegates could be even more lopsided.

They say they’ve seen camps within Maryland’s Republican Party — moderates, traditional and social conservatives, and those with libertarian leanings — gelling in support of Romney.

Scores of tea party activists were among more than 700 people who turned out late last month for a weekday town hall with Romney.

“For a Wednesday afternoon, without much warning, that turnout said a lot,” said Nick Loffer, grass-roots director of Americans for Prosperity Maryland.

It was Romney’s only campaign stop in Maryland — even as behind the scenes his supporters have continued a pattern of leaving little to chance — in a contest expected to break much the way Northeast states have for Romney.

The pro-Romney super PAC Restore Our Future has purchased nearly $400,000 worth of television ad time in the Baltimore market, according to industry estimates. In the two weeks leading up to Tuesday’s election, that expenditure has blanketed much of the state’s Interstate 95 corridor, its capital and blue-collar Baltimore suburbs with commercials almost as frequent as those seen during Maryland’s last gubernatorial race.

Santorum’s campaign, which faces a potential momentum-stopper if he loses Tuesday in Wisconsin, inquired about the cost of television in Maryland, station ad representatives said, but he never purchased any ads. Santorum has not campaigned in Maryland.

Former House speaker Newt Gingrich made a pass through Annapolis last week and is expected in Frederick on Monday. Ron Paul drew a large crowd of college students Wednesday at the University of Maryland.

Tuesday’s primaries in Maryland and the District — where moderate Republicans also have little to no political voice — will unfold on the periphery of the night’s perceived big prize in Wisconsin.

But that has not bothered many in Maryland. Party leaders note their delegates and the District’s 16 add up to 53, more than the 42 at stake in the Badger State.

“We matter, for the first time in a long time,” said Mark Uncapher, a telecommunications lawyer in Bethesda who chairs the Montgomery County Republican Party.

Uncapher, who made up his mind for Romney in the summer, said one reason Maryland’s results will be relevant Tuesday is that he thinks they will reinforce a national narrative of the Republican Party coalescing behind Romney.

“A lot of it is the timing,” Uncapher said. “And quite frankly, as someone who supported [Sen. John] McCain four years ago, it’s fascinating to see how the perceptions have changed. Back then, Romney was the more conservative candidate. Now, he’s the moderate.”

Todd Eberly, an assistant professor of political science at St. Mary’s College, said it will not be surprising if Maryland heavily favors Romney.

“If you look at the exit polling from where Romney has won, he’s won in areas with income that was higher and where folks were better educated. High income, high education; that pretty much describes the entire population of Maryland.”

The campaign that Romney supporters have been running in the state speaks to Maryland’s special brand of Republicans. The headline event before Tuesday’s big vote? No fiery rally about Obama’s health-care program but a meet-and-greet Sunday to discuss foreign policy with former U.N. ambassador John R. Bolton.

“Winning here in Maryland and in D.C. on Tuesday will mark another significant step to show that Romney is the only truly national candidate left,” Bolton said after wooing more than 100 who packed the Royal Kosher restaurant in the northern Baltimore suburb of Pikesville with talk of how dangerous and ineffective Obama’s stance on Iran has been.

“The sooner we get our act together and everybody comes back into focus on the main event, the greater the likelihood we’ll win” the general election, Bolton said. Romney, he said, is the only candidate suitable to “sit at the big desk” and make important decisions looming on U.S. foreign policy.

Still, polls show Romney winning with less than a majority of the state’s Republican voters. While he is expected to win convincingly in Baltimore and Montgomery counties, the state’s two biggest concentrations of Republican voters, he may lose delegates in the state’s rural eastern and western flanks.

“There are areas of the state where Santorum could still do quite well,” Eberly said. Much the way Democrats win in the state, however, if Romney carries the suburbs of the District and Baltimore, he will win easily.

The question is whether Romney will be moderate enough, said Wayne T. Gilchrest, a Republican who represented Maryland’s 1st District in Congress for 18 years. He said he would have preferred to vote for former Utah governor Jon Huntsman Jr.

“The term moderate does not begin to describe the person with the intellect needed to deal with the complex issues we are facing in the 21st century,” Gilchrest said.