Senate Majority Leader Harry Reid (D-NV) on Monday questioned why Republicans in Congress believed wealthy individuals should be able to hide their political donations to campaign groups.

"Thomas Jefferson once said, 'The end of democracy will occur when government falls into the hands of lending institutions and moneyed incorporations,'" he said on the Senate floor. "Campaign finance reforms protected against the kind of corruption Jefferson foresaw by limiting political spending by corporations. Then the Supreme Court issued its Citizens United decision, rolling back a century of work to make elections transparent and credible. The result of Citizens United has been a flood of corporate, special-interest campaign spending by shadowy front groups with questionable motives. Not since the days of Teddy Roosevelt – a Republican who put a stop to unlimited corporate donations – has America seen this kind of out-of-control spending to influence elections."

The DISCLOSE Act, which was up for a procedural vote in the Senate on Monday, would prevent outside campaign groups from hiding their donors. The bill would require organizations that spend $10,000 or more during an election cycle to file a report with the Federal Election Commission within 24 hours and identify any donors who gave $10,000 or more. It would also require the head of any organization that puts out a political ad on TV or radio to publicly state that he or she approves the message, similar to what candidates must do now.

Senate Republicans voted to block the bill on Monday. But Democrats said they plan to hold onto the Senate floor late into the night and force a second vote on the bill on Tuesday.

"Contrary to Republican claims, this legislation wouldn’t require organizations to turn over membership rosters or lists of grassroots donors," Reid added. "Rather, it would prevent corporations and wealthy individuals from using front groups to shield their donations from disclosure. Yet my Republican colleagues – with rare exception – have lined up against this common-sense legislation."

"Their newfound opposition to transparency makes one wonder who they’re trying to protect. Perhaps Republicans want to shield the handful of billionaires willing to contribute nine figures to sway a close presidential election?"

Watch video, uploaded to YouTube by Senate Democrats, below:

[Updated after publication to reflect Senate vote]