This blog has argued that the reason Barr, Viguerie and other conservatives were trying to take over the (formerly) Libertarian Party was to turn it into a vehicle to attack the Republicans for nominating McCain. They want to strip votes away from McCain on the Right so that he will lose. This, they hope, will bring back the dominance that the far Right previously held in the party, but which they lost out to the neo-cons.
In other words their goal is NOT to build the (formerly) Libertarian Party but to use the party as a means of taking over the Republican Party. The LP is but a tool for their use, which shows the naivety of those Libertarians who argued that having Barr lead the ticket “would build the party”. Of course to accomplish that goal Barr can’t really run as a Libertarian. He doesn’t want the libertarian vote, he wants the conservative vote.
See the rest at Classically Liberal