It would be deliciously ironic if Washington’s same-sex marriage law—liberalism’s most recent monument to tolerance—were actually undone by the intolerance of its authors. And while that’s not necessarily likely to happen, a court decision reached this week offers a clear blueprint for how it could.

To review, Washington’s euphemistically titled “Marriage Equality Act” was signed into law by Gov. Gregoire earlier this month and could go into effect by December, pending the outcome of an almost certain voter initiative to overturn it this fall. In the meantime, however, a federal judge in Tacoma issued a ruling on Wednesday in a seemingly unrelated case that addresses many of the same objections gay marriage opponents did in their unsuccessful battle.

In the latter case, Stormans Inc. v. Selecky, Judge Ronald B. Leighton ruled that a 2007 Washington law requiring all pharmacies to dispense so-called “Morning-After” birth control pills was unconstitutional because it violated the First Amendment rights of those who refused to sell the product on religious grounds.

To paraphrase, Leighton ruled that the pharmacists shouldn’t be forced to choose between earning a living and exercising their constitutionally protected rights to religious freedom. And by a strange coincidence, that’s precisely the argument many lawmakers were trying to make last week when they attempted to attach an amendment to the same-sex marriage bill that would protect independent contractors such as photographers and caterers from lawsuits if they refused to work at gay weddings because of religious or philosophical objections.

Backers of the bill killed that amendment, however, arguing that no such provision was needed or warranted even though similar lawsuits have been filed on just that basis in other states that have legalized gay marriage. But in their eagerness to show how tolerant they are of a behavior they don’t object to in the first place, same-sex marriage supporters may have embedded a fatal flaw in the statute by completely disregarding the principled—and constitutionally protected—objections of those who see the world differently.

Again, same-sex marriage and pharmacists dispensing birth control pills may appear at first glance to have little in common. But the unifying standard undergirding both is the notion that no one should be compelled to engage in a commercial transaction that violates their religious convictions.

And if you can invalidate one law on that basis, why not another?