Harriet Miers’s confirmation hearings are about to begin, so we may be on the verge of learning something meaningful about the president’s choice to replace Justice Sandra Day O’Connor on the Supreme Court.

Or maybe we won’t. We haven’t learned much since she was named, and one suspects there might not be all that much more out there.

I don’t know enough about Ms. Miers even to guess at her qualifications for the job to which she has been appointed. I’ve heard good and bad things about her from those who’ve dealt with her, and I’ve read reams of opinion about her, but I still have to count myself as skeptical, as nothing I’ve heard thus far even begins to convince me that she belongs on the Supreme Court.

The case for Miers is simple. The president knows her and likes her. She’s a hard worker and a woman who did well as a lawyer in Texas, is devoted to the president and has performed loyally as a White House staffer.

Oh, and there is one other thing. Ms. Miers regularly attends church and apparently takes her religion seriously. This, according to White House arm twisters, tells us that she would vote on the court in a way that would please social and religious conservatives.

In fact, it tells us no such thing.

It’s nice to know that Ms. Miers is a regular church-goer, and nicer still that she is devout, but we have been told time and again by the same people selling her candidacy today that a nominee’s religious views need not shape his or her judicial decisions. When liberals questioned whether John Roberts would, as a Catholic, be able to decide cases involving abortion and euthanasia without being unduly influenced by the views of his church, they were assured in no uncertain terms that his views of the Constitution and the role of the Supreme Court, rather than his personal religious views, would prove determinative in such cases.

They were right then and wrong now. One can find devout liberals and conservatives sitting side by side in pews every Sunday. As a practical matter, while it is true that regular attendance may, as numerous polls suggest, indicate a greater statistical likelihood that one will vote Republican, such attendance tells us little about any individual attendee’s politics and absolutely nothing about how Harriet Miers might vote on cases that come before her as an associate justice of the Supreme Court.

When a Supreme Court justice looks at a case, conservatives and most other Americans would hope that he or she would ask how the Founders might have viewed it in light of the meaning of document they crafted rather than how their minister, priest or the president who appointed them might want it to turn out. We don’t know how Harriet Miers views the Constitution or the role of a Supreme Court justice, and most of us are waiting to find out.

Still, I have from the beginning been willing to grant that, since few of us know much about the lady, she may be all the president and his advisers claim. She is, after all, a smart woman and a fairly successful lawyer who may well have thought deeply, though privately, about constitutional questions in spite of the rather mundane chores for which she’s billed her clients over the years, but it is going to be up to her to demonstrate it.

What is most troubling about this whole affair, however, is the way the administration has gone about trying to demonize conservatives who have raised questions about Ms. Miers. It began from day one to attack personally the motives, loyalty and judgment of anyone who questioned the wisdom of the nomination. Since then, the ad hominem attacks on Miers’s conservative critics have been unconscionably heavy-handed and will haunt the president regardless of how the nomination fight turns out.

Most conservatives have stood with Bush from the beginning. Those of us who know him like him. We’ve swallowed policies we might otherwise have objected to because we’ve believed that he and those around him are themselves conservatives trying to do the right thing against sometimes terrible odds. We’ve been there for him because we’ve considered ourselves part of his team.

No more.

From now on, this administration will find it difficult to muster support on the right without explaining why it should be forthcoming. The days of the blank check have ended because no thinking conservative really wants to be part of a team that requires marching in lock step without question or thought, even if it is headed by the president of the United States.

Keene, chairman of the American Conservative Union, is a managing associate with Carmen Group, a D.C.-based governmental-affairs firm (www.carmengrouplobbying.com).