The final argument President George Bush used in defense of Supreme Court nominee Harriet Miers was personal. Trust me, he said, “I picked the best person I could find.” Conservatives considered trusting the president and they considered the court over the next 15 or 20 years and their anti-Miers Web sites went online.

The reason given by Ms. Miers for her departure Thursday was that the Senate’s Judiciary Committee would want documents and testimony about her career in the White House, information that she properly points out should remain confidential. The tension between these two demands – the Senate’s understandable desire to understand her record; the White House’s need for confidentiality – meant her nomination could not

continue. (This scenario, it is worth noting, was described by columnist Charles Krauthammer a week ago. Interesting that he and fellow columnist George Will did more to direct the outcome of this nomination than, say, Vice President Dick Cheney or Senate Majority Leader Bill Frist.)

The protests against Ms. Miers fell roughly into two camps: She lacks the qualifications; and she might not be conservative enough. Especially following John Roberts, now the chief justice of the court, a near absence of writing that explained her judicial philosophy looked disqualifyingly thin. No one knows how conservative she would have been, but the right wing of the Republican Party is selective in its faith, and it was not willing to extend it to her.

Democrats were pleased to watch Republicans disagree with each other and uncertain of whether opposing Ms. Miers would result in the president choosing someone more definitely conservative. Their silence, coming after Majority Leader Harry Reid’s tepid support of Ms. Miers positions them well, for a change. And the collapse of the Miers nomination now gives them a tool they had been fearful of using, the filibuster. Their argument would be simple: If Republicans can kill a nomination, why can’t they?

All of this puts enormous pressure on President Bush. His next major decisions, including the replacement nomination, will determine whether Republicans speak plainly about the post-Bush era or just continue quietly preparing for it. It is a brutal calculation, on display now in Congress as both houses try to end the spending patterns of the last several years while meeting the clear demands created by Hurricane Katrina. The president’s pledge in New Orleans to do whatever it took to rebuild the stricken Gulf Coast is slowly being tempered by a sense that affordability matters almost as much.

The president’s next choice, whenever it comes, should reflect the experience of the Miers nomination and the conditions her withdrawal created. That means choosing a conservative with a background impressive enough to quiet a filibuster. It also means not going back to earlier lower-court nominations that caused the questions of the filibuster and the nuclear option to arise this year. At the very least, it means much closer consultation with Republican senators than occurred when Ms. Miers was selected.