DENVER—Marijuana advocates racked up big wins in this year’s session of the Colorado Legislature. Now they’re turning their sights to a bigger effort—full legalization on the 2012 ballot.

Pot legalization backers hope to start gathering signatures as soon as this summer to put the question to voters. Given Colorado’s low signature threshold for ballot initiatives, which currently stands at about 86,000 people, they say they expect an easy path to the polls.

Colorado voters defeated a legalization measure in 2006, as did California voters last year. But activists here are regrouping for another push.

“We’re going to have a great legalization debate in 2012,” predicted Laura Kriho of the Cannabis Therapy Institute, a powerful grass-roots organizer that alerts marijuana advocates to lobby public officials on measures related to pot.

Lawmakers heard from activists several times during the 2011 session that ended last week, and they achieved some surprising victories.

Advocates defeated a proposal to set a driving-high impairment standard that was backed by law enforcement. They quickly squashed a proposal to ban edible marijuana, and dispensaries chipped away at some residency rules and other requirements through a revision of marijuana regulation that had been adopted the year before.

With lobbyists working Capitol halls and a network of marijuana patients packing committee hearings, Colorado’s pot community won over lawmakers on many measures intended to crack down on the nascent industry.

“With each passing legislative session, we’re seeing marijuana and the marijuana distribution system further entrenched and accepted in the state,” said Brian Vicente, head of Sensible Colorado.

Now they’re turning back to the public. Next month, SAFER Colorado and other groups plan to finish work on a proposed ballot measure to make marijuana legal for all adults, not just those with certain medical conditions. After getting the language cleared by state elections officials, supporters can gather signatures.

“We’ve had medical marijuana out there now for more than 10 years without any of the terrible things they said were going to happen. We haven’t seen an increase in accidents, in visits to emergency rooms, in crime—we haven’t seen increases in anything bad,” Kriho said.

Even a prominent critic of Colorado’s marijuana industry, Republican Attorney General John Suthers, said last week that he welcomes a debate on whether pot should be legal. Suthers has argued that recreational pot users have subverted Colorado’s medical marijuana program.

“We have a system right now of state-sponsored fraud,” Suthers said.

Suthers said he’d oppose legalization but welcomed another ballot measure on the idea. “At least a legalization debate will be an honest across-the-board discussion of whether we really want to make this legal,” he said.

Marijuana advocates believe they can win that argument, and they have reason for confidence.

They prevailed over law enforcement over setting DUI limits for THC, the psychoactive ingredient in marijuana. Police backed a 5 nanogram blood-content limit. Marijuana advocates blasted lawmakers with e-mails and phone calls opposing the pot DUI bill, and a bipartisan group of senators rejected the measure.

The bill failed in the Legislature’s closing days after even some conservative Republicans complained the 5 nanogram level seemed an arbitrary indication of whether a driver is impaired. Pot patients toasted the bill’s demise with a victory party the final night of the legislative session.

“It’s great the Legislature didn’t take action on such a harmful bill that wasn’t grounded in evidence,” said Mason Tvert, head of SAFER Colorado, a pro-legalization group.

Pot advocates’ biggest loss was a new requirement that caretakers—people who raise pot for a small number of patients—be required to register with the state. Caregivers argued that health officials, but not police, should know who is growing pot, and they complained that making the caretaker registry public would put home growers at greater risk of theft.

Lawmakers stuck with the registry but exempted it from state open records law, blocking public access to the list of caretakers and their addresses.

That requirement came in a larger marijuana regulation adjustment that affects many aspects of how pot is grown and sold. The measure, which awaits the signature of Gov. John Hickenlooper, loosened residency requirements for non-owners who work in dispensaries and required pot shops to treat patient records as medical records, among other things.

Hickenlooper hasn’t said yet whether he’ll sign the bill. But the governor, along with lawmakers from both parties, seems to be shrugging off a warning letter sent last month by Colorado’s top federal prosecutor, John Walsh.

Walsh warned that state employees who administer marijuana regulations could risk federal prosecution. The letter was similar to ones sent by federal prosecutors in other medical marijuana states, including Washington, where Gov. Chris Gregoire vetoed legislation to license marijuana dispensaries after the Justice Department said it could result in a federal crackdown.

Hickenlooper said that he didn’t share Gregoire’s fear that regulations would bring federal drug raids.

“If the medical marijuana facility is conforming to our regulations, I would assume the federal government will not raid it,” Hickenlooper said Thursday.