NEW YORK — Washington state and Colorado set up a showdown with federal authorities by legalizing recreational use of marijuana in votes on Tuesday.
The outcomes for those ballot measures were a milestone for persistent, but often thwarted, activists who for decades have pressed the causes of drug decriminalization.
‘‘Today, the state of Washington looked at 70 years of marijuana prohibition and said it’s time for a new approach,’’ said Alison Holcomb, manager of the campaign that won passage of Initiative 502 in Washington.
Governor John Hickenlooper of Colorado, a Democrat who opposed legalization, was less enthused. ‘‘Federal law still says marijuana is an illegal drug, so don’t break out the Cheetos or Goldfish too quickly,’’ he said.
Among other ballot questions nationwide, California voters backed a plan to raise income taxes on the wealthy and sales taxes to alleviate a budget crisis, and Maryland voters approved a measure allowing illegal immigrants to pay in-state college tuition.
The measures on marijuana will probably pose a headache for the Justice Department and the Drug Enforcement Administration, which consider pot an illegal drug. The Department of Justice has declined to say how it would respond if the measures were approved.
Colorado’s Amendment 64 will allow adults over 21 to possess up to an ounce of marijuana, though using the drug publicly would be banned. The amendment would allow people to grow up to six marijuana plants in a private, secure area.
Washington’s measure establishes a system of state-licensed marijuana growers, processors, and stores, where adults can buy up to an ounce. It also establishes a standard blood test limit for driving under the influence.
The Washington measure was notable for its sponsors and supporters, who ranged from public health experts and wealthy high-tech executives to two former top Justice Department’s officials in Seattle, US Attorneys John McKay and Kate Pflaumer.
‘‘Marijuana policy reform remains an issue where the people lead and the politicians follow,’’ said Ethan Nadelmann of the Drug Policy Alliance, which opposes the so-called ‘‘war on drugs.’’ “But Washington state shows that many politicians are beginning to catch up.’’
Estimates show pot taxes could bring in hundreds of millions of dollars a year, but the sales won’t start until state officials make rules to govern the industry.
The Washington measure was opposed by Derek Franklin, president of the Washington Association for Substance Abuse and Violence Prevention.
‘‘Legalizing is going to increase marijuana use among kids and really create a mess with the federal government,’’ Franklin said. ‘‘It’s a bit of a tragedy for the state.’’
In Oregon, a marijuana-legalization measure was defeated. In Massachusetts, voters approved a measure to allow marijuana use for medical reasons, joining 17 other states. Arkansas voters rejected a similar measure.
In all, 176 measures were on the ballots Tuesday in 38 states, said Initiative and Referendum Institute at the University of Southern California.
Other notable results:
■ In California, voters approved Governor Jerry Brown’s proposal to raise income taxes on those making more than $250,000 a year and sales taxes on everyone to help balance the state budget and avoid about $6 billion in cuts, mostly to schools.
■ The Maryland measure allowing illegal immigrants to pay in-state college tuition requires the students to have attended a state high school for three years and show they filed state income tax returns during that time.