The bill is expected to face unanimous Republican opposition.
CNN said the bill, known as the Disclose Act, is in response to a 5-4 U.S. Supreme Court ruling this year in Citizens United vs. FEC that removed longtime restrictions on corporate and union political ad spending.
The Democratic proposal, scheduled for a vote Thursday, is designed to bring more transparency to campaign ad spending by corporations, unions and other independent groups, CNN said.
Republicans unanimously blocked a similar proposal last month. A top Senate GOP leadership aide said Wednesday he doesn't expect any Republican defections in the new vote, CNN said.
Senate Republican Leader Mitch McConnell said Democrats are playing politics by scheduling the vote just weeks before the midterm elections, CNN reported.
"In the middle of the worst recession in memory, the Democrat leadership has decided to spend the next two days on the same failed, partisan campaign spending bill aimed at giving Democrats a political edge," McConnell said.
Republicans also contend the bill would violate free speech rights.
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