Last night in Texas marijuana legalization supporter Beto O’Rourke defeated incumbent Rep. Silvestre Reyes in the Democratic primary for Texas’ 16th congressional district. O’Rourke won 50.5 percent to Reyes 44.3 percent, winning the party’s nomination outright and avoiding a run off. Given the district’s heavy democratic leaning, O’Rourke is all but assured to win the general election this November.

While the election was about much more than O’Rourke’s support for legalizing marijuana and Reyes’ opposition to it , the issue did play a role. O’Rourke rose to national prominence in 2009 as an El Paso city councilman when he championed a resolution calling for a national conversation about drug policy reform.

O’Rourke won the election through a variety of factors. One of the biggest problems for Reyes was that he was dogged by numerous ethical issues, which the O’Rourke campaign focused on. In addition O’Rourke benefited significantly from the support of the Super PAC Campaign for Primary Accountability, which has spent money trying to unseat incumbents in both parties this year.

Still O’Rourke’s victory last night is remarkable. It is extremely rare for an incumbent to lose their party’s primary, especially when the  incumbent still technically has the support of the party’s top leaders, including President Obama.

O’Rourke’s win means Congress will likely gain another voice for marijuana legalization.  That’s important given that Congress will lose two of its most prominent marijuana reform advocates next year with the retirement of Rep. Barry Frank (D-MA) and Rep. Ron Paul (R-TX).

His win shows that openly supporting marijuana legalization is no long a third rail in American politics. Reyes’ campaign even tried to make a campaign issue out of O’Rourke support for drug policy reform, running campaign ads about it, but it failed to stop O’Rourke from winning. Public support for marijuana legalization has grown rapidly in the past several years, and it is time for politicians to follow the electorate.

David Dayen has more at FDL News.