"The Democratic Party is ``saying to millions in its progressive wing: 'Take it or leave it, we're not as bad as the Republicans and besides, you've got nowhere to go,''' Nader said. ``Once people know they have somewhere to go, the Democrats will either shape up or shrink down.'' (Ralph Nader, "Nader: Democrats to blame for losses", Yahoo! News (AP), 8/4/00.)
Substitute "Republican" for "Democratic" and "conservative" for "progressive." You're seeing it on this thread.
The paleos are saying that if the Republican Party doesn't conform to their ideology, remaking the GOP into their image, they're going to take their toys and leave. Fact is, the paleos left the party long ago. They moved to the Reform Party when Buchanan took over; they moved to the Libertarian Party and to the Constitution Party. They may flirt with the Republicans from time to time, but they'll never be a driving force in the GOP.