Medical marijuana has been legal in a number of states for years.  Another state – Massachusetts – legalized medical pot tonight, becoming the 18th such state.

But in a historic first, Colorado and Washington have legalized marijuana for recreational purposes today.

As ABC News reports, the Feds will probably quickly challenge the states’ legislation:

Even though the issues have passed, they are likely to meet legal challenges very quickly.

In 2005, the Supreme Court struck down a California law that legalized medical marijuana in the state. The Court said Congress had the power to criminalize marijuana under the Commerce Clause.