The DISCLOSE Act is dead, but the bill’s Senate champions said today they will continue to push for campaign disclosure via regulatory channels and to work to overcome uniform GOP opposition.

In a Capitol Hill press conference staged alongside corporate reform advocates, Sens. Sheldon Whitehouse (D-R.I.) and Jeff Merkley (D-Ore.) touted a Securities and Exchange Commission proposal that would require public companies to report their political spending.

“We need to have corporate accountability,” said Merkley, who noted that the SEC proposal has drawn a record 292,406 public comments. Merkley also called on the IRS to better enforce tax laws that govern politically active nonprofits.

Senate Democrats urged the SEC and the IRS earlier this year to improve political money disclosure through stricter rules or better enforcement. The Supreme Court’s 2010 ruling to deregulate political spending has unleashed millions in unrestricted donations to super PACs, which publicly report their donors, and to politically active nonprofits, which do not.

The Senate’s rejection this week of the DISCLOSE Act in two separate votes moves those regulatory initiatives to the fore. Not a single Republican joined with Democrats in votes Monday and Tuesday to proceed to debate on the bill, which would require groups spending more than $10,000 on political ads to disclose their donors above a $10,000 threshold.

Whitehouse and Merkley were joined by representatives of the Coalition for Accountability in Political Spending, a bipartisan group of state officials led by New York City Public Advocate Bill de Blasio. A diverse Corporate Reform Coalition of public interest and other groups has also been pushing the SEC proposal, as well as a Shareholder Protection Act authored by Sen. Bob Menendez (D-N.J.).

Whitehouse said today that there were “a few slivers of light” in the disclosure bill’s failure to win cloture this week. The first was floor comments Tuesday by Sen. Lisa Murkowski (R-Alaska) endorsing disclosure in principle but voicing reservations about the Whitehouse bill. The second, Whitehouse said, was opposition from Sen. John McCain (R-Ariz.) on the grounds that the bill unfairly favored unions.

Whitehouse said he thinks that McCain is “factually mistaken,” adding he still hopes to convince McCain “there is no special benefit here for labor unions. Everyone is treated exactly the same across the board.”

Whitehouse added that he has spoken with GOP colleagues who privately support the bill but who face pressure from Senate Minority Leader Mitch McConnell (R-Ky.) to oppose it. McConnell has said the bill infringes on free speech and will invite donor harassment.

“There is considerable difficulty within the GOP over the position that Leader McConnell has obliged them to take,” Whitehouse said. He added that some Republican colleagues have expressed fears about political fallout, telling him, “We are one scandal away from owning this mess.”

Murkowski said in her floor comments that she has been and will continue to discuss disclosure legislation with her colleagues on both sides of the aisle. But she acknowledged that this Congress has essentially run out of time to address the issue.