The U.S. Chamber of Commerce needled labor groups in its latest push to stop lawmakers from approving a new campaign finance law. 

The Chamber circulated a new video looking to play up concerns the Disclose Act, a campaign finance reform bill favored largely by Democrats, would clamp down on corporate spending in elections while doing little to regulate unions’ spending. 

The Chamber is ramping up its efforts ahead of an impending vote on the Disclose Act, which was crafted in response to a Supreme Court decision freeing up corporate and labor spending in elections. 

“As you’ll see in the video, The Disclose Act limits the speech of businesses and the associations that represent them in order to prevent them from expressing their political views,” Chamber spokesman Bryan Goettel wrote in an e-mail. “Even worse — while businesses are silenced, labor unions and some of the largest special interest groups in Washington effectively get a pass.”

The Chamber has sought to frame the legislation as restricting organizations’ free speech rights, and now are saying it unfairly disadvantages business.

Senate Majority Leader Harry Reid (D-Nev.) filed cloture Thursday night on the legislation, with an intent to bring it up for a key procedural vote on Tuesday, which will test if it has the 60 votes necessary to escape a filibuster. It’s not clear where the Senate’s 59 Democrats expect to pick up a Republican vote; at least one Republican who’d been thought likely to support it, Sen. Scott Brown (Mass.), came out against the Disclose Act earlier this month.