The LP's infamous pledge

I wonder if the two dominant political parties in America have pledges to stop any non-purists from (gasp!) joining their party....Nope. Hmmmm...I wonder why they're so successful?

Well, they're not "principled," though. So what if they keep winning all the elections and using their ever-increasing power to destroy liberty. Libertarians, thank you very much, would rather keep their principles. You see, for them, principles are more important than liberty.

Wait a minute...