Senator Charles Schumer is supporting legislation that would limit anonymous political donations.
The Disclose Act would require groups that spend $10,000 or more on election advertisements to publicly list their donors.
It would also end the practice of anonymous spending through non-profit groups.
This bill was previously voted down along party lines.
"If you believe in the First Amendment, you believe in disclosure. You believe in sunlight. You believe that letting people know, giving people as close to what people would call 'perfect knowledge' makes the system better," Schumer said.
Senators supporting the bill say it still allows people to spend as much as they want; it just makes the process more transparent.