Lawmakers are still debating whether to act against a Supreme Court ruling on campaign finance.

A House Financial Services subcommittee is considering an idea put forth by Reps. Mike Capuano (D-Mass.) and Alan Grayson (D-Fla.) to make company shareholders vote on any corporate political spending.

On Thursday morning, lawyers were testifying before lawmakers about the feasibility of such a corporate governance law to curb the Citizens United   ruling that lets corporations spend freely on election campaign ads.

Both the Shareholder Protection Act (HR 4537 ) and the End the Hijacking of Shareholder Funds Act (HR 4487 ) were introduced in January by lawmakers concerned that corporations could crowd out citizen voices in campaigns. On the Senate site, Sherrod Brown (D-Ohio) offered a similar bill (S 3004 ).

It's unclear whether any of the bills will pass. Only HR 4537 has cosponsors, and some legal experts say lawmakers can't limit a ruling made by the Supreme Court.

Campaign finance activists have lined up to back the shareholder vote idea. One of the biggest grassroots campaigns for it came from U.S. PIRG, a lobbying and advocacy group that claims to represent the public interest.

"No one will ever have to wonder if their invested money is supporting a cause they don't believe in," U.S. PIRG Advocate Lisa Gilbert said.

-- Ambreen Ali, Congress.org

Correction: An earlier version of this story incorrectly stated the number of cosponsors for HR 4537.