Like teenagers dashing across the tracks in front of an advancing locomotive, Senate Democrats are strutting their stuff at the Capitol, threatening to filibuster the Supreme Court nomination of appeals court Judge Samuel Alito.

Sen. Robert Byrd of West Virginia, grand master of the pork barrel, on Monday chastised Senate Majority Leader Bill Frist for threatening to stop any such effort through a parliamentary step dubbed "the nuclear option."

"If he ever tries to exercise that, he's going to see a real filibuster if I'm living and able to stand on my feet or sit in my seat," said Sen. Byrd. "I'm 88 years old, but I can still fight, and fight I will for freedom of speech. I haven't been here for 47 years to see that freedom of speech whittled away and undermined."

After which, the senator added -- somewhat curiously -- that Democrats haven't really threatened to filibuster Alito, anyway. In response to Sen. Byrd's denials, Sen. Frist, R-Tenn., read from half a dozen news stories, each quoting Democratic senators publicly invoking the filibuster option.

The Democrats in question assert Judge Alito's views on issues such as voting rights could provoke a filibuster unless he allays their concerns about his commitment to civil rights at confirmation hearings beginning Jan. 9. But no one really believes Judge Alito wants to keep blacks from voting. This is all about the Democrats' need to rally their constituents by convincing them such Republican nominees seek to outlaw all abortions on their way to creating a fundamentalist theocracy.

If the minority believe Judge Alito lacks the intellect or temperament to adhere to a sacred oath to protect and defend the U.S. Constitution, the Democrats will have every right and opportunity to marshal that case during an orderly and public debate. If their case is credible, surely at least six Republicans will join them in defeating this nominee in a straight up-or-down vote.

But that's not what Sen. Byrd wants, of course. His interpretation of "freedom of speech" would justify tying up the only pay phone in a burning theater rather than allowing someone to use the line to summon the fire department. He wants the freedom not to submit the Alito nomination to a majority vote on its merits -- the only kind of political "speech" that counts, in the long run.

The Democrats are free to spend Christmas pulling on Santa's boots and strutting about the workshop while the Big Guy is away. But come January, they will have to decide whether Judge Alito is so unqualified -- such a threat to the Republic -- that it's worth violating earlier pledges and going "all in" over this nomination.

The risk they take is that Republicans will call their bluff, employ the "nuclear option," and clear the way to rule as majority party, leaving the minority to issue fatwas of dissent from their booth at the Palm over on 19th Street.