In an effort to preserve a map they believe will help them gain a seat in the U.S. House, Maryland Democrats are challenging the State Board of Elections' decision to certify that opponents of Gov. Martin O'Malley's congressional redistricting plan gathered enough signatures to put the plan on November's statewide ballot.

The Maryland Democratic State Central Committee filed suit Tuesday in Anne Arundel Circuit Court alleging that the board accepted thousands of invalid signatures -- allowing the largely Republican opponents of the map to reach the 55,736  they needed to put the convoluted district map before the voters. The redistricting plan was crafted by O'Malley and the Democratic leadership of the General Assembly and automatically became law this year when the legislature did not vote to disapprove it.

The lawsuit takes direct aim at Maryland Republicans' use of a web-based site, MDPetitions.com, to gather many signatures on line. The site, operated by Del. Neil Parrott of Washington County, has emerged as an effective way for the state GOP to challenge acts of the General Assembly through the referendum process.

The suit contends that the computer-generated process does not meet the requirements of state law for gathering voter information. For that and other reasons, it contends that more than 5,000 of the 59,201 signatures the board certified last week -- enough to knock the measure off the ballot -- should be invalidated.

Jared DeMarinis, director of the board's Candidacy and Campaign Finance Division, said the agency does not comment on pending litigation.

The map is believed to give state Democrats, who now control six of the state's eight congressional districts, a good chance of picking up a seventh in the district now represented by Republican Rep. Roscoe Bartlett.

Parrott released a statement criticizing the Democrats' suit.

“Frankly, I’m surprised Maryland Democrat Leaders are suing to stop the people of Maryland from voting on the redistricting map this coming November," he said. "The current map suppresses minority voting interests and divides communities.  With this lawsuit, they are actively working to suppress voters throughout Maryland.”