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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)

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."