SAN FRANCISCO — To the red-and-blue map of American politics, it may be time to add green. The movement to legalize marijuana, the country’s most popular illicit drug, will take a giant leap on Election Day if California and four other states vote to allow recreational cannabis, as polls suggest they may.

The map of where pot is legal could include the entire West Coast and a block of states reaching from the Pacific to Colorado, raising a stronger challenge to the federal government’s ban on the drug.

In addition to California, Massachusetts and Maine both have legalization initiatives on the ballot next month that seem likely to pass. Arizona and Nevada are also voting on recreational marijuana, with polls showing Nevada voters evenly split.

The passage of recreational marijuana laws in Alaska, Colorado, Oregon and Washington over the past four years may have unlocked the door to eventual federal legalization. But a yes vote in California, which has an economy the size of a large industrial country’s, could blow the door open, experts say.