Four decades after Richard Nixon declared drugs “public enemy No. 1 in the United States,” the tide has turned on marijuana legalization. States are racing to follow Colorado and Washington in ending prohibition, and national politicians are scrambling to get out of the way.

In the Senate, big names from both parties support a bill — the Compassionate Access, Research Expansion and Respect States (CARERS) Act — that would move marijuana out of Schedule I, the designation for heroin and other drugs with “no currently accepted medical use,” and into Schedule II, a group of substances that doctors can prescribe under certain circumstances. And in an interview with Vice’s Shane Smith, President Barack Obama tacitly confirmed that the federal government would now let individual states proceed at their own pace. Think of it as the gay marriage strategy for surviving social change while in national office: Stay agnostic and let the states take care of it.

But marijuana legalization and marriage equality are more different than they first appear. For one thing, in its more prohibitionist days, the federal government already established its primacy over state drug laws. In the 2005 Supreme Court decision Gonzales v. Raich, a confusing 6-3 ruling (with Sandra Day O’Connor, Clarence Thomas and William Rehnquist dissenting), the court ruled against a California medical marijuana patient whose use was legal under state law. The justices found that the commerce clause allows Congress to regulate the interstate drug market and that the only way to do that effectively is to regulate drug use within states.

The Drug Enforcement Agency operates according to the Controlled Substances Act (CSA), not state law, and “It’s legal within city limits!” is not a defense the feds recognize. The Obama administration has said it will exercise discretion, but you can hardly count on the government not to enforce the law.

Because the Constitution requires states to give “full faith and credit” to legal proceedings in other states, same-sex couples could challenge their home state to recognize a marriage performed elsewhere. But there’s no constitutional right to smoke and no obvious way for individuals to sue for their weed, even if it’s medicinal and legal under a revised federal law. As public records, marriage licenses fall under the full faith and credit clause, but prescriptions do not. Oregon State Appeals Court Judge Ronald D. Thom confirmed as much in 2010, when he ruled against Joel Dennis Berringer, a California medical marijuana patient who thought his prescription would be recognized in Oregon, which also has a medical marijuana law. Thom ruled that Berringer’s arrest for possession was legitimate, since California law could protect him only from California law enforcement. Cases like this one show that marijuana legalization has to come through legislation, not the courts.