If Barr was allowed to garner Texas' 34 electoral votes in this way, and neither of the major candidates was able to reach 270 without Texas, then the House of Representatives would decide. Some states which normally vote Republican have Democratic majorities among their House delegations, and other states are evenly split, so it would be hard for McCain to reach a majority. But I can't see the people of the United States allowing such a circus to take place. The last time the House decided an election was in 1825 following the 1824 election, when the first party system (Federalists vs. Jeffersonian Republicans) had broken down. In that case no one had close to 50% of the popular vote, whereas it is quite possible that McCain will pass 50% of the popular vote.
What B.S.
Any voter can vote for any slate of electors he wants. This is about listing on the ballot and following the statutory law that is clear (and the Secy of State admits is clearly in favor of Bob Barr's claim--but says they can overrule it based on judicial activism [that thing that conservatives supposedly don't like]).
Besides, it seems to me that it would be the DEMS and the GOP, if anyone, who are "trying to deny," if that were the case. They are the ones who didn't file their candidates within the statutory limit and are trying to amend their slates after the deadline.