Former New Mexico Gov. Gary Johnson went on offense against Newt Gingrich Monday, attacking the former House speaker’s proposal to execute marijuana users as hypocritical, considering the GOP contender has himself admitted to smoking pot.

Johnson is currently seeking the Libertarian Party nomination for president, and is a proponent of legalizing the drug.

“Ideas are important, especially in a presidential campaign,” said Johnson. “But some of Speaker Gingrich’s ideas over the years are nothing short of scary. Under his legislation, anyone coming home to the U.S. and caught carrying enough marijuana (2 oz.) to distribute would be sentenced to life imprisonment with no parole — or if caught twice, would be sentenced to death.”

Gingrich defended the legislation, the Drug Importer Death Penalty Act of 1996, in November as a way to get tough on Mexican drug cartels.

“This from someone who has admitted his own past marijuana use,” Johnson complained, “saying ‘it was a sign we were alive and in graduate school.'” In 1981, Johnson added, Gingrich introduced a bill to permit “therapeutic use” of cannabis.

“On drug policy alone, I am beginning to see what Rick Santorum means when he talks about the former Speaker having an idea a minute,” Johnson surmised. “We are talking about millions of Americans’ lives here, and having positions ranging from embracing medical marijuana to the death penalty for possessing a small amount of that same substance is astounding both in its hypocrisy and its inconsistency.”

Gingrich won Saturday’s South Carolina Republican primary, and has rebounded in Florida polls ahead of the Sunshine State’s Jan. 31 primary, a stunning coup after placing fourth in the Iowa caucuses and New Hampshire primary this month.

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