WASHINGTON — Marijuana would be legal federally in states that already have approved the drug’s use under a bill introduced Thursday by U.S. Sens. Cory Gardner and Elizabeth Warren.

The measure, which faces a tough path to becoming law, wouldn’t legalize the drug in states that haven’t sanctioned its use or sale.

But in states such as Colorado that have legalized marijuana, it would bring the cannabis industry out of its current financial limbo by giving the industry access to banks and other financial institutions, which previously have been off-limits because of federal prohibitions.

“We just want the federal government to get out of the way,” Warren said.

The alliance between Gardner and Warren represents a bit of a political odd couple, but even the combined effort of a Colorado Republican and Massachusetts Democrat may not be enough to get the legislation through Congress.

In all, 46 U.S. states and several territories have legalized cannabis in some fashion. Some allow cannabidiol, or CBD, products for specific health conditions; others have put in place medical marijuana programs; and 10 permit recreational cannabis use.

Whether this state-level popularity translates to a change in federal law remains to be seen.

Gardner said the bill already had at least four co-sponsors on the Senate side but admitted that there was a “significant education push we have to do” to garner more support.

For Gardner, the current effort represents the latest turn in a roller-coaster relationship that he’s had with marijuana and the Trump administration since the start of the year.

Much of the drama started in January, when U.S. Attorney General Jeff Sessions rolled back Obama-era policies that generally left alone states that sanctioned marijuana.

The move prompted Gardner to use Senate rules to block appointments to Justice Department for several weeks. Gardner ultimately lifted those holds after he said he received assurances from President Donald Trump that the Justice Department would back off.

Both Gardner and Sessions are scheduled to appear at the coming 2018 Western Conservative Summit in Denver.

This is a developing story that will be updated.