Rep. Chris Van Hollen (D-Md.) has filed a lawsuit against the Federal Election Commission in an attempt to force outside groups that engage in "electioneering communications" to disclose the identity of their donors.  

Van Hollen's lawsuit challenges current FEC regulations, passed in the wake of the Supreme Court's landmark Citizens United decision, that permit nonprofit groups like Crossroads GPS to conceal the identity of their donors.

The suit argues that disclosure requirements previously enacted by Congress "have been significantly loosened by the FEC's interpretation."  

"The lawsuit I am filing today seeks to restore the statutory requirement that provides greater disclosure of the donors who provide funding for electioneering communications," Van Hollen said in a statement Thursday. "If this standard had been adhered to, much of the more than $135 million in secret contributions that funded expenditures in the 2010 congressional races would have been disclosed to the public."

Conservative-friendly outside groups, many of which were not required to disclose their donors, spent millions of dollars supporting Republicans in last year's midterm elections as Democrats in Congress decried their involvement.

In 2010, Van Hollen championed the DISCLOSE Act through the Democratic-led House, which was aimed at dissuading business interests from spending on political campaigns. The bill did not pass the Senate.

Along with the lawsuit, Van Hollen is filing a petition with the FEC asking the agency to adopt tougher rules on so-called independent expenditure groups. 

"It is imperative the FEC change its regulations to properly reflect the laws enacted by Congress," Van Hollen said. "The Supreme Court has determined that corporations may make political expenditures. However, it did not intend for them to do under the cover of darkness."

Van Hollen's lawsuit comes as the White House is engaged in its own effort to force companies vying for government contracts to disclose recent political contributions. The Obama administration is drafting an executive order that would require the disclosure, which top Republicans have labeled an abuse of executive authority and an end-run around free speech.

Democrats, meanwhile, have already formed several outside structures to compete with conservative interests during the 2012 cycle. Two new Democratic Super PACs will focus exclusively on House and Senate races next cycle and activist David Brock has formed American Bridge to take on the conservative group American Crossroads.