Why IS Judith Miller in jail?

Among the many remaining questions in the Rove/Plame/Wilson/Miller/Cooper/Bush...scandal is why exactly Judith Miller went to the pokey. Conventional wisdom states that she didn't want to give up her source, but, as Digby points out, she hasn't had trouble in the past:

"One of the things missed in all the paeans to Judy's martyrdom to the confidential source is that the Jeanne D'arc of the Gray Lady had been known to burn her sources without a second thought if it suits her. Seems Judy has some shifting standards when it comes to betraying the reporter's privilege:

In April, Miller interviewed an expert from the Henry L. Stimson Center in Washington on background, then made up a quote and attributed it to the person, who she then named.

So, before we get all gooey about Judy's great sacrifice in fighting for the reporter's privilege, maybe we need to ask whether or not she believes in it in the first place. The evidence suggests that she doesn't.

So why is she in jail?" (Hullabaloo)