Senators sparred Monday over controversial campaign finance legislation, with Democrats accusing Republicans of protecting corporate interests by blocking the bill and the GOP arguing that the majority has misplaced priorities.

Senate Democrats late last week abruptly decided to try to force a vote on legislation undoing part of a January Supreme Court decision dealing with campaign spending. The ruling lifts the limits on what corporations and labor unions can spend on campaigns.

Tuesday’s Senate vote on the DISCLOSE Act will be a “true test of many of our Republican colleagues,” said Senate Democratic Conference Vice Chairman Charles Schumer (N.Y.), who is one of the bill’s chief architects.

It is “one of the most important things we’ll be voting on in the next decade,” Schumer added.

President Barack Obama, meanwhile, delivered an afternoon speech from the Rose Garden, charging Republicans with obstructionism. GOP Senators are vowing to filibuster the bill.

“The Republican leadership in the Senate is once again using every tactic and every maneuver they can to prevent the DISCLOSE Act from even coming up for an up-or-down vote,” Obama said. “Just like they did with unemployment insurance … just like they’re doing by blocking tax credits and lending assistance for small-business owners.

“A vote to oppose these reforms is nothing less than a vote to allow corporate and special interest takeovers of our elections,” he added. “It is damaging to our democracy. It is precisely what led a Republican president named Theodore Roosevelt to tackle this issue a century ago.”

Minority Leader Mitch McConnell (R-Ky.), however, dismissed those claims. He said Democrats were focusing on election-year politics and fundraising rather than the No. 1 issue on Americans’ minds: the economy.

“The mere suggestion that a bill designed to save politicians’ jobs should take precedent over helping millions of Americans find work is an embarrassing indictment of Democrats’ priorities,” McConnell said in a statement. “The DISCLOSE Act seeks to protect unpopular Democrat politicians by silencing their critics and exempting their campaign supporters from an all out attack on the First Amendment.”