Hickenlooper tweeted his declaration Monday and sent an executive order to reporters by email after the fact. He told reporters he didn't want to make a big deal about the proclamation, a decision that prevented a countdown to legalization as seen in Washington, where the law's supporters gathered to smoke in public to celebrate.
Fewer than two dozen people publicly marked Colorado's legalization day. A small group puffed away at 4:20 p.m. on the steps of the state Capitol, with no arrests and no police officers in sight.
"It smells like freedom," said a smiling, puffing Timothy Tipton, a longtime marijuana activist.
Colorado law gave Hickenlooper until Jan. 5 to declare marijuana legal. He told reporters Monday he saw no reason to wait and didn't see any point in letting marijuana become legal without his proclamation.
"If the voters go out and pass something and they put it in the state constitution, by a significant margin, far be it from myself or any governor to overrule. I mean, this is why it's a democracy, right?" Hickenlooper said.
Adults over 21 in Colorado may now possess up to an ounce of marijuana, or six plants. Public use and sale of the drug remain illegal.
Colorado and Washington officials both have asked the U.S. Department of Justice for guidance on the laws that conflict with federal drug law. So far the federal government has offered little guidance beyond stating that marijuana remains illegal and that the Controlled Substances Act will be enforced. Of special concern for state regulators is how to protect state employees who violate federal drug law by complying with state marijuana laws.
The U.S. Attorney's Office issued a statement Monday shortly after Hickenlooper's announcement restating its position.
Hickenlooper also announced a state task force Monday to help craft the marijuana regulations. The 24-member task force includes law enforcement, agriculture officials and marijuana advocates.
The governor admonished the task force not to ponder whether marijuana should be legal.
"I don't think we benefit anyone by going back and turning over the same soil. Our job is to move forward," he said.
Hickenlooper told the task force to "work to reconcile Colorado and federal laws such that the new laws and regulations do not subject Colorado state and local governments and state and local government employees to prosecution by the federal government."
Colorado's marijuana measure, Amendment 64, was approved with 55 percent of the vote last month. One of the authors of Colorado's pot amendment, Mason Tvert, called the declaration "truly historic."
"We are certain that this will be a successful endeavor and Colorado will become a model for other states to follow," Tvert said in a statement.
Find Kristen Wyatt at http://www.twitter.com/APkristenwyatt