RICHMOND, Va. — A federal judge today allowed three Republican presidential hopefuls to join Texas Gov. Rick Perry’s lawsuit challenging Virginia’s ballot access law.

U.S. District Judge John A. Gibney Jr. granted a motion by former House Speaker Newt Gingrich, former Utah Gov. Jon Huntsman and former Pennsylvania Sen. Rick Santorum to intervene in the lawsuit.

Perry filed the lawsuit last month after failing to obtain enough signatures of registered voters to get on Virginia’s GOP presidential primary ballot. Gingrich also failed to qualify, leaving former Massachusetts Gov. Mitt Romney and Texas Rep. Ron Paul as the only candidates who will appear on the ballot for Virginia’s March 6 presidential primary. Huntsman, Santorum and Minnesota Rep. Michele Bachmann (who quit the race Wednesday) did not submit any petitions.

Virginia requires candidates to submit the signatures of at least 10,000 registered voters, including at least 400 from each of the state’s 11 congressional districts, to be placed on the ballot. Perry submitted about 6,000 signatures by the Dec. 22 deadline.

Perry maintains that Virginia’s requirements are unconstitutional because they violate his freedoms of speech and association.

He also challenges the part of Virginia’s law that says signatures must be gathered by a state resident, claiming that the requirements “restrict the number of message carriers” and even prevents him from soliciting signatures for his own campaign.