On Wednesday, House Speaker Paul Ryan announced that he won’t be seeking re-election in 2018. That will leave Ryan’s House seat in Wisconsin’s 1st District open. And while it’s not the most vulnerable seat the GOP has to defend in 2018, it’s far from safe.

This graphic (data is from Daily Kos Elections) shows Trump’s 2016 margin of victory in every currently Republican-held House district as well as the difference between Trump’s margin and Romney’s margin in each district. Wisconsin’s 1st District is highlighted.

Ryan’s district might not be competitive if the national environment was neutral. Wisconsin’s 1st District moved right in the 2016 election. Trump won the district by 10 points after Romney took it only by four points in 2012 (though 2012 may be an odd case because Ryan was the GOP’s vice presidential nominee). And in 2008, Barack Obama won the area by about three points while winning the national popular vote by seven, suggesting that it took a real step to the right over the course of the last four to eight years. If you add that to Ryan’s incumbency advantage, you get a district that wouldn’t typically be near the bottom of the GOP’s list of worries.