The savage drug war in Mexico. Crumbling state budgets. Weariness with current drug policy. The election of a president who said, “Yes — I inhaled.”

These developments and others are kindling unprecedented optimism among the many Americans who want to see marijuana legalized.

Doing so, they contend to an ever-more-receptive audience, could weaken the Mexican cartels now profiting from U.S. pot sales, save billions in law enforcement costs, and generate billions more in tax revenue from one of the nation’s biggest cash crops.

Said a veteran of the movement, Ethan Nadelmann of the Drug Policy Alliance: “This is the first time I feel like the wind is at my back and not in my face.”

Foes of legalization argue that already-rampant pot use by adolescents would worsen if adults could smoke at will.

Even the most hopeful marijuana activists doubt nationwide decriminalization is imminent, but they see the debate evolving dramatically and anticipate fast-paced change on the state level.

“For the most part, what we’ve seen over the past 20 years has been incremental,” said Norm Stamper, a former Seattle police chief now active with Law Enforcement Against Prohibition. “What we’ve seen in the past six months is an explosion of activity, fresh thinking, bold statements and penetrating questions.”

Some examples:

– Numerous prominent political leaders, including California Gov. Arnold Schwarzenegger and former Mexican presidents, have suggested it is time for open debate on legalization.

– Lawmakers in at least three states are considering joining the 13 states that have legalized pot for medical purposes. Massachusetts voters last fall decided to decriminalize possession of an ounce or less of pot; there are now a dozen states that have taken such steps.

– In Congress, Rep. Dennis Kucinich, D-Ohio, and Sen. Jim Webb, D-Va., are among several lawmakers contending that marijuana decriminalization should be studied in re-examining what they deem to be failed U.S. drug policy. “Nothing should be off the table,” Webb said.

– National polls show close to half of American adults are now open to legalizing pot — a constituency encompassing today’s college students and the 60-something baby boomers who popularized the drug in their own youth. In California last month, a statewide Field Poll for the first time found 56 percent of voters supporting legalization.

That poll pleased California Assemblyman Tom Ammiano, a San Francisco Democrat who introduced a bill in February to legalize marijuana in a manner similar to alcohol — taxing sales to adults while barring possession by anyone under 21. Ammiano hopes for a vote by early next year and contends the bill would generate up to $1.3 billion in revenue for his deficit-plagued state.

Ammiano, 67, said he has been heartened by cross-generational and bipartisan support.

“People who initially were very skeptical — as the polls come in, as the budget situation gets worse — are having a second look,” he said. “Maybe these issues that have been treated as wedge issues aren’t anymore. People know the drug war has failed.”

A new tone on drug reform also has sounded more frequently in Congress.

At a House hearing last month, Rep. Steve Cohen, D-Tenn., challenged FBI Director Robert Mueller when Mueller spoke of parents losing their lives to drugs.

“Name me a couple of parents who have lost their lives to marijuana,” Cohen said.

“Can’t,” Mueller replied.

“Exactly. You can’t, because that hasn’t happened,” Cohen said. “Is there some time we’re going to see that we ought to prioritize meth, crack, cocaine and heroin, and deal with the drugs that the American culture is really being affected by?”

In a telephone interview, Kucinich noted that both Obama and former President Bill Clinton acknowledged trying marijuana.

“Apparently that didn’t stop them from achieving their goals in life,” Kucinich said. “We need to come at this from a point of science and research and not from mythologies or fears.”

Gil Kerlikowske, chief of the Office of National Drug Control Policy, has not endorsed the idea of an all-options review of drug policy, but he has suggested scrapping the “war on drugs” label and placing more emphasis on treatment and prevention. Attorney General Eric Holder has said federal authorities will no longer raid medical marijuana facilities in California.

Nonetheless, many opponents of pot legalization remain firm in their convictions.

“We’re opposed to legalization or decriminalization of marijuana. We think it’s the wrong message to send our youth,” said Russell Laine, police chief in Algonquin, Ill., and president of the International Association of Chiefs of Police.

Marijuana — though considered one of the least harmful illegal drugs — consumes a vast amount of time and money on the part of law enforcement, accounting for more than 40 percent of drug arrests nationally even though relatively few pot-only offenders go to prison.

According to estimates by Harvard University economist Jeffrey Miron, legalization of marijuana could save the country at least $7.7 billion in law enforcement costs and generate more than $6 billion in revenue if it were taxed like cigarettes and alcohol.

Pot usage is pervasive. The latest federal survey indicates that more than 100 million Americans have tried it at some point and more than 14 million used it in the previous month.

Testifying recently before Congress, Arizona Attorney General Terry Goddard said U.S. demand for pot is a key factor in the Mexican drug war.

“The violence that we see in Mexico is fueled 65 percent to 70 percent by the trade in one drug: marijuana,” he said. “I’ve called for at least a rational discussion as to what our country can do to take the profit out of that.”

The U.S. Drug Enforcement Agency remains on record against legalization and medical marijuana, which it contends has no scientific justification.

“Legalization of marijuana, no matter how it begins, will come at the expense of our children and public safety,” says a DEA document. “It will create dependency and treatment issues, and open the door to use of other drugs, impaired health, delinquent behavior, and drugged drivers.”

The DEA also says marijuana is now at its most potent, in part because of refinements in cultivation.

Even in liberal Vermont, with the nation’s highest rates of marijuana usage, many substance-abuse specialists are wary of legalization.

Annie Ramniceanu, clinical director at Spectrum Youth and Family Services in Burlington, Vt., said her agency deals with scores of youths each year whose social development has been hurt by early and frequent pot smoking.

“They don’t deal with anything,” she said. “They never learned how to have fun without smoking pot, never learned how to deal with conflict.”

Legalization proponents acknowledge that pot use by adolescents is a major problem, but contend that decriminalizing and regulating the drug would improve matters by shifting efforts away from criminal gangs.

“The notion that we have to keep something completely banned for adults to keep it away from kids doesn’t hold up,” said Bruce Mirken, communications director of the Marijuana Policy Project.

As for Obama, the activists don’t expect him to embrace the cause at this point.

“Obama’s got two wars, an economic disaster. We have to realize they’re not going to put this on the front burner right now,” said Allen St. Pierre, executive director of NORML, or the National Organization for the Reform of Marijuana Laws. “But every measurable metric out there is swinging our way.”

On the Net:

Marijuana Policy Project: http://www.mpp.org

Drug Enforcement Agency: http://www.usdoj.gov/dea

– Article from the Associated Press.