Gary Johnson, the Libertarian Party presidential candidate, was not on the ballot in Oklahoma, and Oklahoma does not permit write-ins. But Johnson was on the ballot in all the states that border Oklahoma. In the 46 counties that border Oklahoma (which includes counties in Texas, New Mexico, Colorado, Kansas, Missouri, and Arkansas), Johnson polled 1.52% of the total vote cast.
If one assumes that Oklahoma would have voted for Johnson at the same level at which voters in neighboring counties voted for him, then Johnson would have polled 20,290 votes in Oklahoma (the Oklahoma vote for President was 1,334,872, and 1.52% of that number equals 20,290).
Johnson is the only minor party presidential candidate in 2012 who was on the ballot in all states bordering Oklahoma, so a similar analysis cannot be made for any other candidate. Jill Stein was not on in Missouri or Kansas; Virgil Goode was not on in Texas, Arkansas, or Kansas.
Oklahoma is a state which has almost always given a higher share of its vote to the Libertarian presidential candidate than that candidate received in the nation as a whole, in the years when the Libertarian has been on the ballot in Oklahoma. In 1980 Ed Clark received 1.07% nationwide but 1.20% in Oklahoma. In 1984 David Bergland received .25% nationally but .72% in Oklahoma. In 1988 Ron Paul received .47% nationally but .53% in Oklahoma. In 1992 Andre Marrou received .28% nationally but .32% in Oklahoma. In 1996 Harry Browne received .50% nationally but .46% in Oklahoma. In 2000 Browne received .36% nationally but .53% in Oklahoma.