Despite the entry of Sen. John Ensign (R-Nev.) into the controversy over who is blocking a bipartisan Senate campaign finance bill, Democrats and government watchdogs said Tuesday that they are still nonplussed as to who is holding up the measure and why.

Ensign did, however, offer some clues Tuesday as to why Senate Democrats failed again in their third attempt to pass a bill that would force Senate candidates to file their campaign finance reports electronically, rather than on paper only.

“I’ve been part of that group that’s been talking about this bill,” said Ensign, who said he “honestly” doesn’t remember whether he originally objected to the bill when it first came up in April.

Ensign, who serves as chairman of the National Republican Senatorial Committee, emerged Monday as the leading suspect for having put the long-standing “anonymous hold” on the bill, because he attempted to offer an amendment to the bill that would force groups that file ethics complaints to also disclose their donors.

But Ensign acknowledged that his decision to come forward with the amendment came in part from leadership talks.

“We certainly discussed it in leadership,” he said.

Indeed, Senate Rules and Administration Chairwoman Dianne Feinstein (D-Calif.), the measure’s chief sponsor, said she was under the impression that Senate Minority Leader Mitch McConnell (R-Ky.) was originally slated to offer the amendment that Ensign put forward on Monday.

Bill Allison, a senior fellow at the Sunlight Foundation, said his group does not believe that Ensign is the original person to place the hold because the nonprofit government watchdog called all 100 Senate offices this spring and were told by Ensign’s staff that he was not the one. Still, Allison said Ensign’s comments are revealing.

“That seems to indicate for the first time that it wasn’t just one Member … but some concerted efforts and internal discussions on this bill in an attempt to block it,” Allison said.

Because an anonymous Republican or Republicans twice objected to passing the bill in April, Allison said the Ensign amendment appears to be a “disingenuous effort to sidetrack it, delay it or kill it.”

Feinstein objected to the Ensign proposal, calling it “not germane” and a potential “poison pill.” However, Ensign said it would prevent outside groups from filing ethics complaints for “purely partisan purposes.”

Feinstein is the primary author of the bill, which she said is needed to provide more transparency in Senate campaign filings as well as put Senate candidates on the same playing field as other federal candidates. Though the previous objections to Feinstein’s attempts to bring up the bill and pass it without debate or amendment were met with ambiguous GOP requests for the ability to offer at least one amendment, Ensign’s objection Monday was the first time a specific proposal was proffered.

Meanwhile, Republicans are still denying that they have an “anonymous hold” on the bill, with Democrats saying they clearly do.

The distinction matters because of new Senate rules requiring people with anonymous holds — which are generally used to indicate an intention to filibuster and serve to prevent measures from passing unanimously — to make their hold public within six days of a bill being submitted for passage on the floor.

McConnell spokesman Don Stewart readily acknowledged that Senate GOP leaders are behind the current objections to the bill, because they want to offer an amendment. Stewart said their objections do not amount to a “hold.”

“I can’t prove there is a hold on the bill,” said Stewart. He added, “If they’d give us an amendment, we’d be done in a half an hour.”

The hallmarks of a secret hold often involve tactics Democrats say the Senate GOP leadership has used in this case: a refusal to come forward and identify specific problems with the bill or specific amendments to be offered.

The second part of that equation was satisfied Monday by Ensign, who said on Tuesday that Republicans have been in talks with Feinstein for “many months.”

However, Feinstein said Republicans only told her last week that they had a specific amendment they wanted to offer.

“Nobody consulted with me. Nobody negotiated with me,” Feinstein said. “I don’t know who they would have been in negotiations with, but not with me. Literally no one has come to me and said, ‘Look, Dianne, if you would do this or do that.’”

Howard Gantman, Feinstein’s staff director on the Rules Committee, added that Feinstein has tried to get more information from Republicans: “After the minority blocked the bill twice on the floor, Sen. Feinstein wrote Minority Leader McConnell asking for his help. His staff said the minority was interested in some possible amendments, but we were never given the details” until last week.