WASHINGTON – The U.S. Senate, famously described  by the Founding Fathers as the saucer that cools the hot tea of the House, has become more of an icebox in recent years in part because of frequent filibusters.

With internal Senate reforms stalled, filibuster opponents now are looking to the courts.

A lawsuit filed Monday by Atlanta-area Democratic U.S. Reps. John Lewis and Hank Johnson, among others, argues that the 60-vote hurdle to conduct Senate business is unconstitutional because it subverts the idea of majority rule.

The lawsuit has a clear political agenda, as the plaintiffs, including government reform group Common Cause, argue they were harmed by the failures of two Democrat-backed bills: The Disclose Act, which would require increased transparency for political spending from outside interest groups; and the Dream Act, which would give a path to citizenship for illegal immigrants who came to the United States as children and go to college or serve in the military.

But if Republicans take over the Senate after the November elections, filibuster reform would help them.

Filed in federal court in Washington, the suit argues that the filibuster gives a minority of one legislative chamber veto power over all three branches of government, by allowing frequent blocking of executive and judicial nominees.

Sarah Binder, a political science professor at George Washington University and co-author of "Politics or Principle? Filibustering in the United States Senate," said courts will likely be skeptical because under the Constitution the Senate has the power to make its own rules. She said the suit is a sign of "pent-up frustration to get the chamber to move legislation, to debate it and follow through."

Prominent Atlanta attorney Emmet Bondurant, the lead plaintiffs' lawyer, said previous lawsuits in this area were "not very well thought out" and that legislative bodies are not allowed to make unconstitutional rules.

The suit notes that both parties have employed the filibuster aggressively – Democrats stalled civil rights legislation in the 1960s and President George W. Bush’s judicial nominees in the 2000s – but Republicans are responsible for a record number of filibusters since Democrats re-assumed control of the body in 2007. They do not come in the form of lengthy speeches that hold up all action -- think "Mr. Smith Goes to Washington" -- but, by agreement, as a silent block on almost any bill or nomination that does not have unanimous support until there is a chance to schedule a vote on "cloture" that requires 60 ayes.

"It has outlived its usefulness as a procedure for the Senate to be able to reach a reasoned decision on legislation," Johnson said.

Republicans argue that it is Democrats who have abused the process by blocking their amendments. They favor keeping the rule.

"Both parties have benefited from the filibuster over the years," said Lauren Culbertson, spokeswoman for Georgia Republican Sen. Johnny Isakson. And if it went away? "Senate Republicans would have no leverage at all."