Supporters of medical marijuana in Minnesota may try to put the question directly to voters.

Last week Gov. Tim Pawlenty vetoed a bill that would have allowed medical use of marijuana for terminally ill patients. He cited law enforcement concerns about expanded drug use.

Medical marijuana backers are preparing to try to put a constitutional amendment — ensuring the right of the sick and dying to smoke marijuana — on the state ballot next year.

A spokesman for the Marijuana Policy Project, a national group pushing the legislation, says the group “would spend what’s needed” on a campaign.