By Glynn Wilson –

Public opinion data now shows beyond a shadow of a doubt that a clear majority of Americans, 58 percent, favor the legalization of marijuana, according to the latest Gallup poll on the subject.

Can the legal system be far behind?

Legalization advocates have seen a “period of unprecedented success” over the past year, according to Gallup, as Washington state and Colorado became the first states to legalize the recreational use of marijuana.

This latest survey shows an 8 percent increase since Gallup last asked the question in October, 2011, and found that 50 precedent of Americans then favored legalization. When Gallup first asked the question in 1969, only 12 percent favored legalization.

Public support for it more than doubled in the 1970s to 28 percent after the social revolution when the Baby Boomers were coming of age and exploring their options. Support plateaued during the conservative backlash period of the 1980s and into the ’90s, but started gaining steam again since the turn of the century in the year 2000.

This year a sizable percentage of Americans, 38 percent, admitted to having tried the herb, which Gallup says “may be a contributing factor to greater acceptance.”

Success at the ballot box in the past year in Colorado and Washington may have increased Americans’ tolerance for marijuana legalization, or their confidence in its success at the state level.

“Support for legalization has jumped 10 percentage points since last November and the legal momentum shows no sign of abating,” Gallup says in its analysis.

Just last week, California’s second-highest elected official, Lt. Gov. Gavin Newsom, said that pot should be legal in the Golden State. Advocates are poised to introduce a statewide referendum in 2014 to legalize the drug there.

The Obama administration has also shown flexible on the matter for the first time, despite maintaining the government’s firm opposition to legalizing marijuana under federal law. In late August Deputy Attorney General James Cole announced the Justice Department would not challenge the legality of Colorado’s and Washington’s successful referendums, provided that those states maintain strict rules regarding the drug’s sale and distribution.

Independents Fueling Growth in Acceptance of Legalizing Marijuana

Independents’ growing support for legalization has mostly driven the jump in Americans’ overall support, according to the data, with 62 percent of independents now favoring legalization. That’s up 12 points from November 2012.

Support for legalization among Democrats and Republicans has shown little change, Gallup says, “yet there is a marked divide between Republicans, who still oppose legalizing marijuana, and Democrats and independents.”

Young Adults More Likely to Support Legalization

Nearly two-thirds, 67 percent, of Americans between the ages of 18 and 29 fully support legalization, along with clear majorities of Americans between the ages of 30 and 64.

Americans 65 and older are the only age group that still opposes legalizing marijuana. Yet even among older Americans, support has gone up 14 percentage points since 2011.

Gallup’s Bottom Line

“It has been a long path toward majority acceptance of marijuana over the past 44 years, but Americans’ support for legalization accelerated as the new millennium began. This acceptance of a substance that most people might have considered forbidden in the late 1960s and 1970s may be attributed to changing social mores and growing social acceptance,” Gallup says in its analysis. “The increasing prevalence of medical marijuana as a socially acceptable way to alleviate symptoms of diseases such as arthritis, and as a way to mitigate side effects of chemotherapy, may have also contributed to Americans’ growing support.”

Whatever the reasons for Americans’ greater acceptance of marijuana, it is likely that this momentum will spur further legalization efforts across the United States. Advocates of legalizing marijuana say taxing and regulating the drug could be financially beneficial to states and municipalities nationwide. While detractors such as law enforcement and substance abuse professionals have cited health risks including an increased heart rate, and respiratory and memory problems, they are losing the public relations battle.

“With Americans’ support for legalization quadrupling since 1969, and localities on the East Coast such as Portland, Maine, considering a symbolic referendum to legalize marijuana, it is clear that interest in this drug and these issues will remain elevated in the foreseeable future,” Gallup concludes.

Survey Methods

Results for this Gallup poll are based on telephone interviews conducted Oct. 3-6, 2013, on the Gallup Daily tracking survey, with a random sample of 1,028 adults, aged 18 and older, living in all 50 U.S. states and the District of Columbia. For results based on the total sample of national adults, one can say with 95 percent confidence that the margin of sampling error is plus or minus 4 percentage points.