Is he the GOP's worst nightmare? Or a non-player in a contest where he might draw Ralph Nader-like numbers?

The fact is, McCain's people don't want to find out. Regardless, Bob Barr, former Republican Congressman from Georgia, is going to toss his hat into the ring as a Libertarian Party candidate for President:

"In the month since we formed our exploratory committee, not a single Republican who has spoken with me to try and convince me not to seek the Libertarian nomination has disagreed with my reasons for considering a run," Mr. Barr told The Times today in an e-mail exchange before leaving London on a flight to Atlanta.

Most Republicans who asked him not to run "also said they understand why I'd run and why John McCain is not conservative and will not seriously tackle the growth in government power and spending," he said. "Some said they would vote for me if I ran, but for the sake of the Republican Party, they would prefer I didn't."

Mr. Barr will speak tomorrow at the National Press Club.

But Republicans, both publicly and behind the scenes, are saying that a Barr run could hurt him financially and sink Mr. McCain's Republican candidacy in the general election, likely against Sen. Barack Obama.

Former House Speaker Newt Gingrich told The Times today that "Bob Barr will make it marginally easier for Barack Obama to become president. That outcome threatens every libertarian value Barr professes to champion."