Republican Senator-elect Mark Kirk may help push through a campaign-finance transparency bill opposed by Republican leaders during the lame-duck session.

Kirk defeated Democratic candidate Alexi Giannoulias for President Obama's former Illinois Senate seat and is one of three new members of the Senate who will be sworn in to the chamber during the lame-duck session.

The Democracy is Strengthened by Casting Light on Spending in Elections Act (DISCLOSE Act) would force groups running election ads to disclose the sources of their funding. In addition, the bill would prohibit foreign corporations, government contractors and TARP recipients from making campaign contributions.

The bill has already cleared the United States House of Representatives but failed to be passed in the Senate due to a Republican filibuster.

The legislation was drafted as a response to the Supreme Court's Citizens United decision, which ruled that limits on political spending by corporations violated the First Amendment and consequently struck down the McCain-Feingold campaign finance laws.

"Unless we enact new disclosure laws, secret contributions to outside spending groups are bound to dramatically increase in the 2012 elections, when both presidential and congressional races will be at stake," said Democracy 21’s Fred Wertheimer.

 "Secret contributions in political campaigns are a formula for influencing-buying corruption."

The American Civil Liberties Union opposes the DISCLOSE Act, which it says could compromise free speech.

"The ACLU supports the disclosure of large contributions to candidates as long as it does not have a chilling effect on political participation, but the DISCLOSE Act would inflict unnecessary damage to free speech rights and does not include the proper safeguards to protect Americans' privacy," said ACLU legislative and policy attorney Michael Macleod-Ball, in a media advisory. "The bill would severely impact donor anonymity, especially those donors who give to smaller and more controversial organizations."

Kirk previously stated he supports enacting new campaign-finance transparency laws, which gives hope to Democrats who seek to pass the bill during the lame-duck session in Congress.

"I broke with my party early and backed the McCain-Feingold campaign finance reform legislation," Kirk said during an Illinois Senate debate in October. "Now we need to go further, and have all candidates disclose contributions within 24 hours on the internet."

It remains to be seen whether Kirk would actually support the bill, which his Republican colleagues unanimously oppose. Additionally, during his campaign for Senate, Kirk referred to himself as the "42nd Republican senator, with the opportunity to put the brakes on any lame-duck overreach."

"Mitch McConnell, the Republican leader, essentially told any member of his caucus that if they voted for it he'd have their head," Democratic Congressional Campaign Committee Chair Chris Van Hollen told reporters at a Christian Science Monitor breakfast. "Because they understood there were a lot of these big special interests that preferred to operate in the dark."

"Kirk should take the lead in pushing a disclosure bill through this lame-duck session of Congress," writes Richard L. Hasen, a professor of law at Loyola Law School, at Politico. "He should also urge the remaining Republican moderates to cross party lines with him."