With Democrats still undecided on launching a rare filibuster of a judicial nomination, Senate Republicans and the White House have targeted a dozen Democrats in the confirmation battle over Miguel Estrada.

Republicans are seeking to win over the Democratic dozen — mostly Southern or Western Senators — even as they have taken the highly unusual step of pushing the business community to get involved in the fight for Estrada’s bid to the U.S. Court of Appeals for the District of Columbia Circuit, often called the nation’s second-highest court.

With ethnic and Supreme Court politics as a backdrop, Senate Republican Conference Chairman Rick Santorum (Pa.) on Tuesday asked a group of high-powered lobbyists he meets with regularly to start pushing Democrats on the Estrada nomination.

“What I’ve been telling the folks in the [business] community is, they have a big stake in the judicial nominating process,” Santorum said Wednesday. “Unless you impact the judiciary, you’ re not impacting the entire process.”

The business community has traditionally stayed on the sidelines as battles over Supreme Court and lower court nominees have unfolded, although in recent years the U.S. Chamber of Commerce and its affiliates have become increasingly involved in the elections of local and state judges.

It’s unclear how much the K Street crowd will heed the call from Republicans to get involved in the Estrada fight. “It’s hard to mobilize the business community on judicial nominations,” one lobbyist, a Capitol Hill veteran himself, said after the meeting. “It’s not an issue that the corporate world has traditionally weighed in on. But they’re looking for help where they can get it.”

Before Tuesday’s meeting broke up, officials from the Republican National Committee handed out a list of Democrats for the lobbyists to pressure: Sens. Bill Nelson (Fla.), Ben Nelson (Neb.), John Breaux (La.), Mary Landrieu (La.), Max Baucus (Mont.), Robert Byrd (W.Va.), Blanche Lincoln (Ark.), Mark Pryor (Ark.), Jeff Bingaman (N.M.), Evan Bayh (Ind.), Tom Carper (Del.) and Zell Miller (Ga.).

With Estrada’s nomination having cleared the Judiciary Committee, he by all accounts has a majority of votes to win confirmation. Even Sen. Lincoln Chafee (R-R.I.), the most unpredictable member of the GOP Conference, said he supports Estrada.

The question remaining for Democrats is whether they will try to launch a filibuster of Estrada, well aware that no nominee to a circuit or district court has ever been defeated by the parliamentary tactic, which would require 60 votes to ensure confirmation. After a Democratic luncheon that focused almost entirely on the Estrada issue, Minority Leader Thomas Daschle (S.D.) said there was still no resolution to the issue and likely wouldn’t be until later this week or early next week, when a first vote of some sort on Estrada’s nomination is likely to occur.

“We can’t really make that decision until we’ve had a bit more time to debate and to see where the votes are,” Daschle said.

Breaux said he was the lone voice of support for Estrada’s confirmation at the Democratic meeting, and also the lone voice opposing any attempt to filibuster.

Momentum in some ways appeared to be building toward taking the bold step of trying to block Estrada via a filibuster. Landrieu, for example, before entering the luncheon, said she didn’t support Estrada’s nomination but also opposed a filibuster. “I would not be involved in the filibuster. I would either be for or against him,” she said.

After the meeting, however, she said she now had an “open mind” toward a filibuster, an idea whose foremost proponents are the staunchest liberals on Judiciary, Sens. Charles Schumer (D-N.Y.), Edward Kennedy (D-Mass.) and Dick Durbin (D-Ill.).

Landrieu said she was swayed by Democrats who believe Estrada has ducked basic questions about his views and not turned over writings produced while he worked in the Solicitor General’s Office during the first Bush administration and the Clinton administration. “There’s a lot of strong sentiment about the violation of the process,” she said.

Bayh, Hollings and Bill Nelson all said they were undecided on the nomination and whether they would support a filibuster.

Ben Nelson, who is planning a meeting with Estrada this week, said he too was undecided and indicated that he has generally opposed filibustering the executive branch’s nominees, although he refused to say which way he was leaning in this case.

Baucus said he opposed the nomination but was also undecided on the filibuster. And in another sign of the uncertainty of whether a filibuster could succeed, Sen. Hillary Rodham Clinton (D-N.Y.) also pointedly declined to endorse a filibuster. “At this point I’m opposing the nomination,” she said.

Schumer said Democrats had a “very strong consensus” that they needed to force Estrada to answer more questions, at a minimum, before allowing a vote.

With Republicans touting Estrada’s Hispanic heritage — his family emigrated when he was 17 — Democrats have put forward a litany of Latino groups opposed to his nomination to defend themselves against any political charge of blocking the first Hispanic from serving on the D.C. Circuit Court.

Some Democrats also want to knock off Estrada because right-leaning judicial observers view him as a reliably more conservative jurist than White House Counsel Alberto Gonzales, and therefore a more likely choice for the Supreme Court.

Ever since the defeat of Judge Charles Pickering’s nomination to a circuit court seat a year ago this month, Republicans have been war-gaming the confirmation fights, trying to drum up outside lobbying pressure from the right. GOP aides have long complained that their interest groups have been slow to get involved in the judicial fights, much slower than liberal-leaning groups such as the People for the American Way and the NAACP.

In recent days, however, conservative groups ranging from the Family Research Council to the American Conservative Union have been sending out blast e-mails to supporters trying to gin up support for Estrada.

Santorum’s talk to K Street lobbyists was another addition to that effort. One lobbyist noted that it was the first time the Pennsylvania Republican had pushed the group to get involved in an issue that the business community had previously considered a social issue.