This isn't true. People who call themselves 'libertarians' seem quite happy to vote for people who are extremely socially conservative. The economics is what they care about (and perhaps pot). Obviously the GOP is very socially conservative, but so are factions of the Libertarian Party. In 2008 the Libertarian Party nominee for President of the United States was Bob Barr:
https://en.wikipedia.org/wiki/Bob_Barr
>During his tenure, Barr was regarded as one of the most conservative members of Congress. In 2002, he was described by Bill Shipp in an OnlineAthens.com article as "the idol of the gun-toting, abortion-fighting, IRS-hating hard right wing of American politics"
>He voted for the first USA PATRIOT Act
>Barr took a lead in legislative debate concerning same-sex marriage. He authored and sponsored the Defense of Marriage Act, a law enacted in 1996 which states that only marriages that are between a man and a woman can be federally recognized, and individual states may choose not to recognize a same-sex marriage performed in another state
>Barr was originally a strong supporter of the War on Drugs, reflecting his previous experience as an Anti-Drug Coordinator for the United States Department of Justice. While in Congress, he was a member of the Speaker's Task Force for a Drug-Free America.
>Barr advocated complete federal prohibition of medical marijuana. In 1998, he successfully blocked implementation of Initiative 59 — the "Legalization of Marijuana for Medical Treatment Initiative of 1998" — which would have legalized medical marijuana in Washington, D.C. The "Barr Amendment" to the 1999 Omnibus spending bill not only blocked implementation of Initiative 59, but also prohibited the vote tally from even being released. Nearly a year passed before a lawsuit filed by the American Civil Liberties Union eventually revealed the initiative had received 69 percent of the vote. In response to the judge's ruling, Barr simply attached another "Barr Amendment" to the 2000 Omnibus spending bill that overturned Initiative 59 outright. The Barr Amendment also prohibited future laws that would "decrease the penalties for marijuana or other Schedule I drugs" in Washington, D.C. This preemptively blocked future attempts by Marijuana Policy Project (MPP) to reform marijuana laws in DC via the initiative process. In March 2002, U.S. District Judge Emmet Sullivan struck down this portion of the Barr Amendment as being an unconstitutional restriction on free speech. Barr's response to the ruling was defiant:
>Clearly, the court today has ignored the constitutional right and responsibility of Congress to pass laws protecting citizens from dangerous and addictive narcotics, and the right of Congress to exert legislative control over the District of Columbia as the nation's capital. —Bob Barr, March 28, 2002