WASHINGTON — Perhaps no group of supporters has been courted as assiduously by the Bush administration as Christian conservatives.

And no senator is closer to this group than Sen. Sam Brownback, R-Kan., who is exploring a run for president with the help of some of them.

So it was a slap in the face to the White House when Brownback, after three days of lobbying by White House aides to win support for Supreme Court nominee Harriet Miers, emerged from an hourlong meeting with her yesterday and said he was prepared to vote against her.

"I still think there's a lot to learn about this nominee," Brownback said, citing doubts about Miers' positions on issues such as abortion and same-sex marriage. "I must do my own due diligence, and I can't say that all these issues are overcome in a one-hour meeting."

Asked if he was prepared to vote against Miers, Brownback said: "Yes."

In a further sign of discontent on the right with the Miers' nomination, White House officials held a quickly organized conference call with several hundred conservatives yesterday afternoon.

The White House also named a prominent former senator and evangelical Christian, Dan Coats, to serve as Miers' adviser during the confirmation process.

White House adviser Jay Sekulow said that assurances from Bush and others had made headway in convincing conservatives Miers would make a good justice. "The base [of the Republican Party] is coming along, slowly but surely," Sekulow said.

White House officials said they were confident Senate Republicans and Democrats would back Miers once they got to know her. She has met with 14 senators.

"We're just at the beginning of the courtesy-visit process," said White House spokeswoman Dana Perino.

Despite the lack of support from Brownback and a few other conservative GOP senators, Bush's choice of Miers — his onetime personal lawyer who now is White House counsel — does not appear in danger in the Senate, at least for now.

But it continues to spark unrest among evangelicals and some other social conservatives, who worked to send Bush to the White House twice on the understanding that he would name well-known conservatives to the Supreme Court.

Paul Weyrich, founder of the Free Congress Foundation and one of the capital's leading conservatives, described the White House efforts to sway skeptical activists as intense.

He said Bush's closest political adviser, Karl Rove, placed four telephone calls over the weekend to James Dobson, founder of the influential evangelical group, Focus on the Family. Rove persuaded Dobson to back Miers. And Dobson has sought to make the White House case but declined to offer details about why he was assured about her.

"He gave us the line, 'Well, I've been told things that I can't share with you,' " Weyrich said. "That drives people up a wall."

Weyrich said that during his 40 years as a conservative activist, Miers is the sixth "trust me" nominee a Republican president has picked for the Supreme Court. In every other case — David Souter, Harry Blackmun, John Paul Stevens, Anthony Kennedy and Sandra Day O'Connor — he said the trust was broken because, in his view, all five turned out to be moderates or liberals on many social issues.

"Can you see why I can't take another one of these?" Weyrich said.

Sen. Lindsey Graham, R-S.C., who like Brownback is a member of the Senate Judiciary Committee that will hold hearings on Miers, also met with her yesterday and described himself as "impressed."

"If people will listen and give her a fair shot, I expect her to be confirmed," he said.

Senate Democrats, meanwhile, have been more low-key about Miers. Some have stepped up demands for papers from Miers' White House years, saying executive privilege is trumped by the need to know her views.

Material from The Dallas Morning News is included in this report.