Texas Rep. Ron Paul and former New Mexico Gov. Gary Johnson, who are both libertarian-leaning Republicans, defended drug legalization during the Fox News presidential debate on Thursday night.

When questioned about why social conservatives should support him, Paul said they should vote for him because his defense of liberty includes their right to practice their lifestyle the way they want. The congressman said liberty needed to be protected "across the board."

"We don't have the first amendment so that we can talk about the weather," he noted. "You have a right to do things that are very controversial."

Government should not tell its its citizens what they can eat and drink, the congressman continued. "Up until this past century -- for over one hundred years -- [drugs] were legal."

"How many people here would use heroin if it were legal?" Paul asked. "Oh yeah, I need to government to take care of me, I don't want to use heroin so I need these laws," he joked, followed by a round of applause from the audience.

"I never thought heroin would get an applause here in South Carolina," quipped moderator Chris Wallace.

Johnson, who has admitted to using marijuana, noted that half of the money spend on law enforcement and prison is drug-related. Ninety percent of the problem is prohibition-related, not use related, according to the former governor.

"That's not to discount the problems with use and abuse, but [prohibition] ought to be the focus," he said.

Marijuana should be legalized and harm reduction strategies should be used for other illegal drugs, Johnson added. "Look at the drug problem as a health issue rather than a criminal justice issue."