The quirks of Maryland’s presidential election year calendar have saved Prince George’s Democratic Congresswoman Donna Edwards from a tough renomination fight.

An exceptionally early primary — April 3 — also will help Republican Congressman Roscoe Bartlett fend off GOP challengers, although his future in November is less certain.

Clearly, the decision by Maryland legislators to move the primary — usually set in September — to early spring in hopes of having an impact on the 2012 presidential selection process has been a boon to incumbents.

It takes lots of time and a truckload (or two) of money to take on an entrenched member of Congress. With just 83 days between the Jan. 11 filing deadline and the April 3 primary, few politicians took the plunge.

In Edwards’ 4th District, former Prince George’s State’s Attorney Glenn Ivey had been making plans to run against the incumbent, whose constituent service has been less than stellar.

Ivey’s broad name recognition, winning record, a legion of supporters and key early endorsements made a run promising.

Also, the new district includes some voters in Anne Arundel County, unfamiliar turf for Edwards.

The problem for the former state’s attorney was a lack of time to raise the wad of cash needed to take on a well-endowed member of Congress.

Edwards can rely on a universe of labor unions and liberal interest groups to out-raise virtually any opponent.

Ivey realized time was too short to counter the incumbent’s fundraising advantages. So he beat a reluctant retreat, leaving Edwards with an easy road to another two-year term.

Bartlett, too, got a break. Even though Democrats in Annapolis sliced and diced his 6th District to make the Republican vulnerable to a Democratic challenge in the general election, the Middletown congressman benefits immensely from an early primary.

Both veteran state Sen. David Brinkley of New Market and freshman Del. Kathy Azfali of Middletown face long odds trying to organize a well-financed challenge in a sharply redrawn district that now takes in a big chunk of Montgomery County as well as much of Frederick County and all of Washington, Allegany and Garrett counties.

Compounding the challengers’ primary problem is the 90-day General Assembly session. Brinkley and Azfali will be glued to their State House seats instead of campaigning furiously to develop name recognition and support from Republicans in the extended 6th District, where they are virtual strangers beyond their state legislative turf.

Until Democratic leaders placed as many Democrats as Republicans in Bartlett’s congressional district, the conservative incumbent hadn’t bothered to raise money for re-election. Since then, he’s shown that financing a campaign is easy after a couple of decades on Capitol Hill. Conservative interest groups and lobbyists are lining up to write checks.

So the veteran congressman should survive this year’s early Republican primary. Unlike Edwards, though, who has nominal GOP opposition in November, Bartlett could be in for the struggle of his political career against Democratic state Sen. Rob Garagiola of Germantown.

National and state Democratic groups will make sure Garagiola isn’t at a financial disadvantage.

Still, it will take a well-organized, high-energy campaign from Garagiola and state Democrats to upset such a deeply entrenched incumbent.

Another Marylander in Congress is thankful for this year’s early primary — Sen. Ben Cardin. He’s got a Democratic challenger in state Sen. Anthony Muse of Prince George’s County. But Muse has neither enough time nor money to seriously contest the Senate nomination.

Like Brinkley and Azfali, Muse is stuck for the duration of the primary in the State House, while Cardin can canvass the state, thanks to plentiful breaks in the U.S. Senate schedule and a bounty of campaign cash he’s been accumulating for six years.

Cardin quickly locked up key African-American endorsements that undercut Muse’s ability to appeal to his key constituency. More Cardin endorsements are sure to follow. Muse is no threat.

Thanks to friendly redistricting or good timing, the rest of Maryland’s congressional incumbents can take it easy. John Sarbanes (3rd District) and Elijah Cummings (7th District) have virtual cakewalks. Chris Van Hollen (8th District) has to familiarize Frederick County voters with his record and value in Congress, but he’s drawn no substantial opposition.

Steny Hoyer (5th District) will breeze through the primary before taking on Del. Tony O’Donnell of Lusby in St. Mary’s County, the House minority leader in Annapolis. O’Donnell’s long odds got longer when redistricting gave Hoyer Democratic strongholds in Prince George’s and Charles counties.

Dutch Ruppersberger (2nd District) will likely face off in November against Republican state Sen. Nancy Jacobs of Abingdon in Harford County, but redistricting gives him an overwhelming advantage.

Finally, 1st District Congressman Andy Harris, thought to be an endangered species, got the luckiest break of all: State Democrats shifted their focus and targeted Bartlett, not Harris, in their attempt to pick up a congressional seat through redistricting. Harris is likely to represent his Eastern Shore district for a long time.

Barry Rascovar is a State House columnist, communications consultant and radio commentator on WYPR-FM, 88.1. He can be reached at brascovar@hotmail.com.