Possession and cultivation of marijuana became legal on December 10, 2012, after governor John Hickenlooper issued an executive action adding Amendment 64 to the state constitution.

[7] Proposed initiative 2011/12 #30 was submitted on January 4 and found sufficient by the Secretary of State on February 27 to appear on the general ballot for the November election.

[12] The legislation defines industrial hemp as any part of the cannabis plant, growing or not, "with a delta-9-tetrahydrocannabinol (THC) concentration that does not exceed three tenths percent (0.3%) on a dry weight basis.

This amendment requires the general assembly to enact an excise tax to be levied upon wholesale sales of marijuana, requiring that the first $40 million in revenue raised annually by such tax be credited to the public school capital construction assistance fund, known as the Building Excellent Schools today (B.E.S.T.)

[17] The largest survey for the amendment, conducted October 23, 2012 by Public Policy Polling, indicated that 53% of voters intended to support it, with 46% opposed.

[20] The outcome is nevertheless expected to have broad impacts south of the border,[21] including in Mexico where less than a week after the U.S. vote Mexican senators submitted a proposal to legalize marijuana in their country.

[22] Though support for liberalizing drug policy has traditionally been considered a liberal or libertarian cause,[23] Amendment 64 garnered a number of high-profile conservative endorsements, including, most notably, an endorsement from former U.S. Representative and 2008 Republican Presidential Candidate Tom Tancredo, who claimed, "Throughout my career in public policy and in public office, I have fought to reform or eliminate wasteful and ineffective government programs.

"[24] Similarly, Temple Emmanuel's Rabbi, Steven Foster, endorsed Amendment 64 because, "as clergy, we have the responsibility to talk about what policies serve our community best.

Proponents believe that permitting recreational use will allow officers to focus on prevention of violent crime and that it will remove some of the burden on the state's prosecutors and courts.

[26] Other justifications for support include: increasing the state's revenue (much of the additional revenue is required to be used to fund primary education),[26] subjecting otherwise illicit substances to health and safety regulations for the protections of users,[27] enhancing individual freedom,[27] eliminating a black market (black markets tend to result in crime regardless of the goods sold because market participants are already criminals, and therefore have less to lose by committing additional crimes),[28] and providing empirical evidence for studying the effects of legalization to identify whether the harms associated with drugs are actually caused by the policy of prohibition.

In particular, the group sees marijuana as addictive and as damaging to children because they believe it "permanently affects brain development, impairs learning ability and contributes to depression.

The board began by saying, "We believe possession and use of marijuana should be legal," but ultimately encouraged readers to vote against the amendments because "Drug policy simply has no business being in the state constitution.

[34] Governor John Hickenlooper officially added the law to his state's constitution on Monday December 10, 2012 making the private consumption of marijuana legal in Colorado.

"[35] On December 10, 2012 Governor Hickenlooper signed Executive Order B 2012-004 to create the Task Force on the Implementation of Amendment 64 to "consider and resolve a number of policy, legal and procedural issues".

[44] The Denver Post disagreed, citing the insufficiency of licensing fees to previously regulate medical marijuana and rejecting the notion that the taxes would drive pot back to the black market.

A tiny majority of El Paso county voters approved the statewide Amendment 64 with an original margin of only 10 votes.

Some council members expressed concern over the effect pot shops would have on existing businesses, as well as on local military bases.

[54] Medical marijuana outlets continue to operate in Colorado Springs although current regulations prevent any new stores from opening.

The county currently limits the industry to 15 retail marijuana stores which produced more than one half million dollars in taxes in their first year.

[62] Colorado has experienced significant financial benefit as a result of legalization, with marijuana tax, license and fee revenue surpassing $1 billion as of 2019.