The marijuana debate

Pot smokers formally gained the right to light up in Colorado on Dec. 10 as Governor John Hickenlooper

signed into effect a controversial ballot measure legalizing marijuana

for adult recreational use in what proponents hailed as a "historic

day."

Mike Momany smokes marijuana, Thursday, Dec. 6, 2012, just after midnight at the Space Needle in Seattle. Possession of marijuana became legal in Washington state at midnight, and several hundred people gathered at the Space Needle to smoke and celebrate the occasion, even though the new law does prohibit public use of marijuana. (AP Photo/Ted S. Warren)

FILE - In this Nov. 6, 2012 file photo, people attending an Amendment 64 watch party celebrate after a local television station announced the marijuana amendment's passage in Denver. Using marijuana for recreational use is now effectively legal in Colorado. Gov. John Hickenlooper declared a voter-approved marijuana legalization amendment as part of the state constitution on Monday, Dec. 10, 2012. It was the last procedural step needed for the amendment to take effect. (AP Photo/Brennan Linsley, File)

Brian Vicente co-director of the Yes on 64 campaign waits to start a news conference about the legalization of marijuana at Civic Center Park in Denver on Wednesday, Nov. 7, 2012. Colorado voters passed Amendment 64 on Tuesday legalizing marijuana in Colorado for recreational use. (AP Photo/Ed Andrieski)

Brian Vicente co-director of the Yes on 64 campaign waits to start a news conference about the legalization of marijuana at Civic Center Park in Denver on Wednesday, Nov. 7, 2012. Colorado voters passed Amendment 64 on Tuesday legalizing marijuana in Colorado for recreational use. (AP Photo/Ed Andrieski)

Betty Aldworth, center, a director of the Yes on 64 campaign responds to questions about the legalization of marijuana at a news conference at Civic Center Park in Denver on Wednesday, Nov. 7, 2012. Co-directors Brian Vicente, left, and Mason Tvert, right, listen. Colorado voters passed Amendment 64 on Tuesday legalizing marijuana in Colorado for recreational use. (AP Photo/Ed Andrieski)

Betty Aldworth, center, a director of the Yes on 64 campaign responds to questions about the legalization of marijuana at a news conference at Civic Center Park in Denver on Wednesday, Nov. 7, 2012. Co-directors Brian Vicente, left, and Mason Tvert, right, listen. Colorado voters passed Amendment 64 on Tuesday legalizing marijuana in Colorado for recreational use. (AP Photo/Ed Andrieski)

People attending an Amendment 64 watch party in a bar hug after a local television station announced the marijuana amendment's passage, in Denver, Colo., Tuesday, Nov. 6, 2012. The amendment would make it legal in Colorado for individuals to possess and for businesses to sell marijuana for recreational use. (AP Photo/Brennan Linsley)

FILE - In this Nov. 6, 2012 file photo, Amanda Jetter celebrates along with others attending an Amendment 64 watch party in a bar after a local television station announced the marijuana amendment's passage, in Denver, Colo. Tuesday's presidential election results showed the American voting public has not only become more permanently diverse in its makeup, but also in its mindset. Voters also altered the course of U.S. social policy, voting in Maine and Maryland to approve same-sex marriage, while Washington state and Colorado voted to legalize recreational use of marijuana. (AP Photo/Brennan Linsley, File)

FILE - In this Nov. 6, 2012 file photo, Amanda Jetter celebrates along with others attending an Amendment 64 watch party in a bar after a local television station announced the marijuana amendment's passage, in Denver, Colo. Tuesday's presidential election results showed the American voting public has not only become more permanently diverse in its makeup, but also in its mindset. Voters also altered the course of U.S. social policy, voting in Maine and Maryland to approve same-sex marriage, while Washington state and Colorado voted to legalize recreational use of marijuana. (AP Photo/Brennan Linsley, File)

A medical marijuana plant is shown at the Northwest Patient Resource Center medical marijuana dispensary, Wednesday, Nov. 7, 2012, in Seattle. After voters weighed in on election day, Colorado and Washington became the first states to allow legal pot for recreational use, but they are likely to face resistance from federal regulations. (AP Photo/Ted S. Warren)

Jake Dimmock, co-owner of the Northwest Patient Resource Center medical marijuana dispensary, works on balancing the pH level of the soil used to grow new medical marijuana plants, Wednesday, Nov. 7, 2012, in Seattle. After voters weighed in on election day, Colorado and Washington became the first states to allow legal pot for recreational use, but they are likely to face resistance from federal regulations. (AP Photo/Ted S. Warren)

Medical marijuana is packaged for sale in 1-gram packages at the Northwest Patient Resource Center medical marijuana dispensary, Wednesday, Nov. 7, 2012, in Seattle. After voters weighed in on election day, Colorado and Washington became the first states to allow possession of up to 1 oz. of legal pot for recreational use, but they are likely to face resistance from federal regulations. (AP Photo/Ted S. Warren)