WASHINGTON -- Vice President Joe Biden said Tuesday that he thinks the Senate has the 60 votes needed to pass a measure to expand background checks on gun purchasers in a key vote set to take place as early as Wednesday, as some senators continued to express doubt.
"I think we're going to be okay," Biden told reporters on Capitol Hill, where he spoke earlier at an event honoring Gabe Zimmerman, an aide to former Rep. Gabrielle Giffords (D-Ariz.) who was killed in the Jan. 2011 shooting massacre in Tucson.
"We are working to get to 60 and it's fluid," Biden said. "I think we're there, but it's not unusual as you all know for people to make up their minds at the last minute."
Surrounded by reporters, the vice president was asked to confirm whether he had just told former Giffords staffer Pam Simon, who was also at the Zimmerman event, that the Senate is two votes shy of having the support to pass the background checks amendment authored by Sens. Joe Manchin (D-W.Va.) and Pat Toomey (R-Pa.). He didn't comment.
As for senators who still say they're on the fence on whether to support tighter gun background checks, Biden said there's "nothing more" that he or anyone can really do to convince them to support it.
"They have to decide,” he said.
Despite Biden's optimism, the vote count is incredibly shaky. As of Tuesday afternoon, 52 senators had publicly declared that they would vote for the legislation, while 39 had said they would vote against it, which leaves nine senators still publicly undecided on how they'll vote.
Supporters of the background checks deal were dealt a blow on Tuesday when Sen. Dean Heller (R-Nev.) announced that he would not be backing the Manchin-Toomey amendment. Democrats had believed that he was one of their top prospects to join them in a deal, since he had called expanded background checks a "reasonable" step forward in the past.
But on Tuesday afternoon, Heller said he was against the deal because he was worried it would result in a federal database of gun owners, even though it explicitly bars the creation of a federal gun registry.
"Despite the good faith efforts of Senators Manchin and Toomey, the onerous paperwork and expansion of federal power mandated in this legislation are too great of a concern. I believe that this legislation could lead to the creation of a national gun registry and puts additional burdens on law-abiding citizens," he said in a statement.
Senators leading the charge for passing the amendment, which is the core piece of President Barack Obama's gun violence package, were cautious on Tuesday when asked where things stood.
Sen. Mark Kirk (R-Ill.) said he was "optimistic" that the votes will be there, but they weren't yet as of Tuesday afternoon. "I think we're not ready for a vote," he said.
"We're working hard on it," said Sen. Charles Schumer (D-N.Y.). "I don't know" if we'll get there, he said, adding, "the NRA is very strong. They are. We know that. We've always known that."
Other senators who say they're still on the fence weren't talking. Sens. Heidi Heitkamp (D-N.D.) and Mark Begich (D-Alaska) both literally ran away from The Huffington Post when asked how they planned to vote. Sen. John McCain (R-Ariz.) said he's still undecided, but "favorably disposed" to supporting it.
For some, the pressure to support the background checks amendment is getting personal. Sen. Jeff Flake (R-Ariz.), who was seen as a possible supporter, announced Monday night that he plans to oppose it. By Tuesday morning, Giffords' husband, Mark Kelly, vowed to use his gun control PAC to try to unseat Flake in the next election cycle over the matter. Flake is good friends with Kelly and Giffords.
Flake also got a talking to from Simon at the Zimmerman event. Simon said she pressed him to "seriously consider" supporting the background checks measure.
"He just said he'd think about it," Simon said. "We want a little more than thinking. We want action."
Simon said she knows Flake is close with Giffords, which is why she is "very disappointed" in his plan to oppose the proposal. She said she was also disappointed in Flake for apparently making his announcement without telling Giffords first.
"I can only hope that he digs deep and votes his conscience," Simon said, "as opposed to the pressures that seem to be on him."
Amanda Terkel contributed reporting.