His platform has some serious flaws, but Paul is the only candidate standing up for individual liberties.
"At least he's not crazy," Democrats observe, explaining why they'd rather lose to Mitt Romney than any other any Republican in the 2012 presidential race. Some are comforted as well by Romney's willingness to say anything or be anything to please his target voters. "At least he's not an ideologue." A cynic merely pretending to embrace ideas or opinions you disdain is preferable to a true believer.
It has been Romney's good fortune to run against a collection of crazies -- self-promoters with delusions of grandeur (Gingrich and Cain) and ignoramuses (Cain, Bachmann, and Perry.) The Republican Party hasn't exactly put its best candidates forward, or (with a notable exception) its most freedom loving. Today, Romney's most energized opponent is theocrat, Rick Santorum, a conservative religious collectivist. As David Boaz, at CATO points out, Santorum is a stated opponent of individual liberty, a critic of what he calls "the libertarianish right... this whole idea of personal autonomy."
Libertarians, right and left, have no candidate in the race, except for Ron Paul (although Former New Mexico Gov. Gary Johnson could conceivably become a third-party factor on a Libertarian ticket). A most imperfect advocate for individual liberty, Paul favors state laws against flag desecration (core political speech) and federal laws against abortion, and he opposes separation of church and state, which is essential to the religious liberty of minorities. Like many religious conservatives, Paul asserts, illogically and counter-factually, that religious majorities are endangered. Religion is under siege in our extremely religious country, he claims hysterically, and children are not allowed to pray in schools. (In fact, the law is clear: children are free to pray in school, individually or in groups; school officials are prohibited from forcing them to pray.)