The Washington State Senate made history on February 1 by voting in favor of gay marriage, and passage in the house appears certain, but potential obstacles for marriage equality remain. Among them: Out-of-state religious groups that want to defeat marriage at the ballot and an anti-gay-marriage attorney general. Here's what's coming:

This week: According to Zach Silk, spokesman for Washington United for Marriage, the Washington State House will vote on the bill this week, probably on Wednesday, February 8. No one expects anything other than easy passage, with plenty of yea votes secured long ago. "That puts it on the governor's desk next week," Silk says.

Next week: Once the governor signs the bill—which has to happen within five days of her receiving it from the legislature—referendum mayhem begins. The National Organization for Marriage recently told the Seattle Times that it will file for a referendum on gay marriage "before the ink is dry on the governor's signature." NOM—which spent millions to repeal marriage equality in California and Maine—will then have 90 days from March 8, the scheduled end of the legislative session, to work with its allies to gather 120,557 valid signatures in support of their referendum. If they don't get the required signatures, gay marriages could begin in mid-June. If they do get the signatures—which they probably will—we'll be voting on gay marriage in November. Assuming it passes, gay marriages will begin after the election is certified sometime in December. But don't get excited yet: No state has ever upheld same-sex marriage at the ballot.

Week after next: You might ask: Who gets to decide what the ballot language should look like? The answer is very interesting: Attorney General Rob McKenna, who opposes marriage equality, will approve of (or begin tinkering with) the ballot title and summary sometime in the week after the referendum is filed. "We're watching Rob McKenna closely," Silk says. "As we all should." recommended