Fallout from the Supreme Court's 2010 Citizens United decision has clouded the outlook for President Obama's nominees to the Securities and Exchange Commission.
Two nominees for the commission saw their candidacies stalled at the committee level this month partly because of a push by Senate Democrats to force the SEC to take on corporate political spending.
Campaign finance oversight would be an awkward role for the SEC, which is tasked with overseeing markets and protecting investors.
But the senators, Chuck Schumer of New York, Elizabeth Warren of Massachusetts, Robert Menendez of New Jersey and Jeff Merkley of Oregon, who voted against the nominees were just carrying out one part of a larger campaign to pressure the SEC to delve into campaign finance as a response to Citizens United.
Schumer and company voted against the two nominees, one Democratic and one Republican, after neither one would commit to backing a rule mandating that companies disclose political contributions.