For two decades, Jeff Sessions represented Alabama in the United States Senate. Earlier this year, President Donald Trump chose Sessions to be Attorney General, and a special election was called to fill his vacant seat. Both parties held their primaries tonight (with 8 Democrats and 10 Republicans running), although (UPDATED 8/16 PM) 72% of the primary vote was cast in the Republican primary.

Not only was the lion’s share of the vote cast on the Republican side, but the GOP primary was an amplified illustration of the divisions which exist among today’s Republicans. Appointed senator Luther Strange (who was heavily backed by the Republican U.S. Senate leadership) faced both former Chief Justice Roy Moore (the favorite of evangelical conservatives) and Congressman “Mo” Brooks (a member of the House Freedom Caucus who was elected in the 2010 Republican/TEA Party wave). Despite vocal establishment support and a last-minute endorsement from President Trump, (UPDATED 8/16 PM) only 33% of Republican primary voters backed the incumbent, while 39% supported Moore, 20% voted for Brooks, while 8% supported one of the other candidates. While the results were a surprise to some, three pollsters (Alabama based Cygnal, Georgia based Trafalgar Group, and Louisiana’s JMC Analytics in this poll) correctly foresaw Moore’s rise and Strange’s structural weakness.

(UPDATED 8/16 PM) Even though Senator Brooks is in the runoff, he should be concerned about the contours of support (or lack thereof) he has across the state. The four urban counties containing Mobile, Montgomery, Birmingham, and Huntsville and cast 31% of the primary vote. These four counties should have been his base, yet he could only outpoll Moore 34-28% (28% went to Brooks, and 10% to other candidates). 18% of the vote was cast in the six suburban counties surrounding these urban centers, and Moore actually won a 37-33% plurality over the incumbent in those suburban counties (17% went to Brooks, and 13% to other candidates). In the 51% of the primary vote that was cast from smaller/more rural counties, Moore swept these 57 counties over the incumbent 46-32% (16% Brooks, and 6% other candidates). Given that the incumbent couldn’t attain 35% in either the urban, suburban, or small-town/rural counties, Strange has an uphill battle in the September 26 runoff, especially considering that both Congressional Republicans and President Trump have already given him a considerable amount of support in the primary.

This race goes into a September 26 runoff, and the winner will face Democrat Doug Jones (who won his primary with 64%) on December 12.