There are many mangers, and many dogs. The two-party system that we have evolved is painful to bear; too painful for Libertarians in particular.
Newsflash! Libertarians are often supported (that means selected and funded) as spoilers by the Democrats ... and as I personally have no doubt .... by the GOPe. The wreck of Cuccinelli is enough, IMNVHO, to condemn the Libertarians to Hell.
I am no fan of Levin, however his advice, viz fight like hell for the conservatives/and or Tea Party in the primaries, but for the winner of those primaries, the non-Democrat, in the election is what I follow.
If God should once again smile upon this Republic in the election of 2016, I shall fight for Levin's idea of a Constitutional Convention with the express purpose of ending popular election of Senators.
The test of my theory will be the Crooked SOB McConnell. If he wins in Kentucky (by no means a sure thing) and acknowledges the Tea Party and the Conservatives in his next term, it might help vindicate my POV.
If he continues his detestable caving in to the other party in exchange for a cut of the swag, and others are like him, well then, I say let's skip the effects of a Third Party, i.e., a century of Democrat hegemony, which is exactly what even mediocre Libertarian results will guarantee, and cut to the shooting war.
LOL