Voters OK recreational use of marijuana in Mass.

Massachusetts voters on Tuesday approved a ballot measure that will allow adults over 21 to use marijuana for recreational purposes.

{mosads}The measure was backed by groups like the New Approach PAC and the Marijuana Policy Project, two long-time supporters of liberalizing marijuana rules. Travel guru Rick Steves gave the Question 4 campaign $100,000.

Both Boston Mayor Marty Walsh (D) and Gov. Charlie Baker (R) opposed the measure. Still, opponents spent less than a third of what proponents dropped into advertising and campaigning.

Massachusetts joins Washington, Oregon, Colorado and Alaska, states where voters approved legalization measures two and four years ago. Voters in four other states — Arizona, Nevada, California and Maine — are deciding Tuesday whether to legalize marijuana.