MADISON, Wis. — Wisconsin's Republican Assembly speaker doesn't believe Democratic Gov. Tony Evers' proposal to legalize medical marijuana and decriminalize small amounts for recreational use will be a success.

Speaker Robin Vos put the chances of Evers' plan passing at 10 percent, telling an audience of Capitol insiders on Thursday that Evers missed an opportunity to score a victory. Evers, who is in his sixth week as governor, might have been able to win support for a narrower proposal limited only to medical marijuana, Vos said.

Vos has been open to that idea for years, even as other Republicans have remained steadfast against any form of legalization. Republicans hold majorities in the state Senate and Assembly.

"There is no chance Republicans are going to go to recreational marijuana," Vos said at the WisPolitics.com luncheon. "They're not going to decriminalize it so people can carry around bags of weed all over the state."

Vos called that idea "so preposterous, because that is so far out of the mainstream, it makes the entire proposal not serious."

Vos cited Evers' plan, along with his rejection of a Republican income tax cut bill, as examples of issues where they could have worked together to find common ground but didn't. Both Evers and Republicans have been talking a lot about wanting to compromise, but so far have shown little signs of actually doing it.

"I just feel like it doesn't have to be this way," Vos said. "A lot of the decision doesn't come from the Legislature, it comes from the way the executive branch chooses to operate."

A spokeswoman for Evers had no immediate reaction to Vos' comments.

Evers on Wednesday vetoed a Republican income tax cut bill , the first measure passed by the Legislature. Vos said it was too early to say whether he would seek a veto override, but to succeed he would need Democratic votes. No Democrats voted for the bill.

Evers is proposing his own income tax cut in his budget next week, which will also include his plan to legalize medical marijuana. Evers, the former state schools chief, also wants to de-criminalize possessing, manufacturing or distributing of up to 25 grams of recreational pot for personal use.

Evers argues it's time for Wisconsin to join more than 30 other states — including neighboring Michigan, Minnesota and Illinois — in legalizing medical marijuana. Wisconsin voters in 16 counties and two cities voted in November to approve non-binding referendums in favor of medical marijuana.

But Vos called the Evers proposal a "very difficult sell." He said a medical marijuana legalization plan had about a 40 percent chance of passing, but that he thought he could get it to 50 percent. The plan Evers put forward only has a 10 percent chance with skeptical Republicans, Vos said.

Vos said the 25 grams of marijuana Evers wants to de-criminalize would be enough to make 50 joints.

"That's almost enough to get this entire room high," Vos said to laughter from the assembled lobbyists, state government workers and other power brokers.

"We should try that sometime," quipped moderator Jeff Mayers, president of WisPolitics.com.