(CNN) House Speaker Paul Ryan's decision to not seek re-election makes his district more competitive for Democrats in the fall.

One would have already expected it to be more competitive than usual given Republicans' poor performance on the generic ballot and in special elections throughout the year. And with Ryan's exit, Republicans are losing a high-profile incumbent who has won re-elections rather easily in Wisconsin's first congressional district.

When you take into the partisan lean of the district, the national environment and the potential quality of the candidates, it's pretty clear that this is going to be a race that both sides fight for.

Based upon the last two presidential elections and how Wisconsin 1 has voted versus the nation, the partisan baseline of Ryan's district is +11 Republican.

The generic ballot has bounced around a little bit, though has generally shown Democrats with a high single digit to low double digit advantage. If that same shift were applied to Wisconsin 1, Democrats would be quite competitive. It's also been noted by the New York Times' Nate Cohn that in open seats where no incumbent is running, shifts in the vote can be even greater than one would suspect just looking at the generic ballot.