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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)

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."