In the early morning hours of May 30, House Democrats found a new (if temporary) best friend: the Tea Party. The House was voting on an uncommon issue: medical marijuana. And surprisingly, the measure that was seen more as a test vote actually passed.


More than 85 percent of the caucus — 170 Democrats — voted in favor of an amendment by Rep. Dana RohrabacherDana Tyrone RohrabacherNow someone wants to slap a SPACE Tax on Jeff Bezos, Elon Musk, et al 'Blue wave' Democrats eye comebacks after losing reelection Former Rep. Rohrabacher says he took part in Jan. 6 march to Capitol but did not storm building MORE (R-Calif.) to the Commerce-Justice-Science Appropriations bill. That amendment would instruct the Drug Enforcement Administration not to enforce federal marijuana laws with respect to medical cannabis in states that have legalized it. However, 170 votes aren't enough for passage. For this measure to pass, Republicans needed to join the ranks, and the most unlikely Republicans came along for the ride.

It's a common theme in Washington that House Tea Party members are a thorn in the side of Democrats and even mainstream Republicans. The Tea Party is blamed for polarization, for gridlock, and for serious policy challenges, including the recent government shutdown. Many of these claims are on point and are items the Tea Party trumpets to media and constituents.

Typically for the Tea Party, concepts like compromise, coalition building and bipartisanship are seen as threats to their principles and are to be avoided. However, for medical marijuana, the Tea Party is right at home voting with liberal Democrats. Are their reasons for supporting such measures the same? Not a chance. But a vote — not the reason for a vote — is all that matters for a roll call.

Conservative support for pot

In total, 49 Republicans joined Democrats on the Rohrabacher amendment — far more than supported a similar measure in a vote in 2012. So, who are these Republicans? Political science research would suggest that the easiest way to build a coalition is to find members ideologically closer to you. For Democrats, those members would be moderate Republicans. And yes, some moderate Republicans voted in favor of the measure.

However, many of the members came from deep red districts — and the numbers back it up. Using the Cook Political Report's district-level Partisan Voting Index (PVI) measure is telling. On average, Republicans supporting the Rohrabacher Amendment came from districts with a PVI of R+10. For perspective, R+10 districts sent to Congress Reps. Michele Bachmann (Minn.), Eric Cantor (Va.) and the representatives from North Dakota, South Dakota and Alaska.

The Republicans voting in favor of the Rohrarbacher amendment came from districts that Republican presidential candidate Mitt Romney won in 2012, on average, by more than 16 percent, and about 41 percent of those Republican members identify as part of the Tea Party.\

In fact, political scientist Keith Poole and others measure the ideology of members based on their voting records after they have served a full term. The scale generally ranges from -1 (most liberal) to 1 (most conservative). The average Republican supporting the Rohrabacher amendment scored a 0.73, making them more conservative than the average House Republican. If it weren't for deeply conservative, Tea Party Republicans from very red districts, the Rohrabacher amendment never would have passed.

How did they come together?

On most issues, it's hard to imagine how two of the most liberal members, like Reps. Barbara Lee (D) and George Miller (D) of California, vote with two of the most conservative members, like Reps. Mick Mulvaney (R-S.C.) and Justin Amash (R-Mich.).

For liberals, the marijuana issue is about civil rights, criminal justice and access to healthcare, among other motivators. Many see government prohibition of marijuana as misguided as government's prior prohibition of alcohol. Conservatives see this issue as one of states' rights and a means of reducing the role of federal influence. After spending years criticizing ObamaCare as government coming between a patient and her doctor, Republicans see prohibitions on medical marijuana as similar interference. Pushing the feds to take a hands-off approach is consistent with both liberal and Tea Party ideologies.

However, this is more than just a principled stand. Members of Congress see the writing on the wall. Public support for medical marijuana has never been higher. The Marijuana Policy Project has recently cited national polls from Fox News and CBS News that show that more than 80 percent of Americans support medical marijuana. The Marijuana Policy Project also cites state polls of support for medical cannabis from a diverse set of states including Idaho (61 percent), Kentucky (78 percent), Maryland (72 percent), New York (82 percent), Ohio (73 percent) and Texas (69 percent).

Public support like this gives many in Congress the political cover to assert their principles — on civil rights, on the 10th Amendment, on health care freedom, etc. And on at least one issue, that political cover makes bipartisan best friends out of liberals and the Tea Party.

Hudak is a fellow in Governance Studies at the Brookings Institution and managing editor of the FixGov blog. Jared Milfred provided research assistance for this piece.