This week, the subpoenas of the House and Senate Judiciary Committees come due for Harriet Miers and Sara Taylor, respectively. And it's been the subject of some speculation that the president's invocation of "executive privilege" will prevent them from testifying meaningfully.

Though the power of the various subspecies of executive privilege to prevent witnesses -- especially former White House officials -- from testifying is highly questionable, it's worth noting that the speculation about whether or not they'll be held in contempt of Congress if they cite the privilege in refusing to answer certain questions (or even testify at all) has so far bypassed the question of what, exactly, constitutes contempt in the first place.

But we might not even have to answer that question directly -- if there really is an answer at all. Instead, ask yourself what happens if these witnesses and others similarly situated come to the committees with the intent of making them actually prove they were in contempt. Though contempt (for all its faults, at least under the statutory contempt process) is the obvious threat here, what if the witnesses simply show up, say words when they're asked questions, and then deny that they were talking gibberish?

If they can make fight number one be about whether or not they really were in contempt at all, that just adds another layer to the fights we're going to have later, such as what power the Congress has to punish that contempt, if contempt it was.

All it ultimately takes to refer a charge of contempt is a majority vote, and Democrats can presumably deliver that. But if it comes without Republican support (as it likely would have to), and the witnesses have appeared as ordered, are on videotape answering questions as they're put to them, and deny having been evasive or offering non-answers, what will be the response to the inevitable Republican accusations that the charges are a "partisan witch hunt?"

Of course, we all know that nothing stops the Republicans from doing that, no matter what happens. Neither does the use of inherent contempt rather than statutory contempt eliminate that danger. But be prepared for that possibility. If the White House wants to run out the clock, there's little reason for them to do anything differently from their game plan so far. "I don't recall" has served them well, and I have a feeling that this invocation of "executive privilege" may turn out to be just a new variation on the same old game.

Don't be surprised, then, if this week's "constitutional showdown" ends in yet another flurry of murmuring and head scratching, as the clock continues to run.

But remember, too, that this represents another necessary step in the path the committees have chosen -- that is, to methodically demonstrate the "administration's" unwillingness to abide by the normal rules of government, and pattern of stonewalling and evasion of oversight. To what end, we will have to wait to see.