If Voters Hate Congress So Much, Then Why Hasn't Any Incumbent Lost a Primary?

Congressional approval is at 11 percent. And voters are gluttons for punishment.

Americans might be mad as hell at Congress — but they're going to keep taking it.

Consider these two facts:

1: Congressional approval is at 11 percent, as measured by the latest Allstate/National Journal Heartland Monitor Poll.

2: Exactly zero incumbent candidates — for the Senate or House — have lost a primary race in this midterm cycle. In Tuesday's congressional primaries, incumbents went 45 for 45, and establishment Republicans won easy victories against their tea-party rivals. Despite how much voters say they hate the current Congress, they still like them better than their primary challengers.

Now, these are just primary elections. Come November, the incumbents could lose out to the other party. That's especially true for Senate Democrats. As Charlie Cook has explained, "A survey of the national landscape finds that open Democratic seats in South Dakota and, to a lesser extent, West Virginia will be extremely difficult for the party to hold."

So what gives with these primary results?

Incumbent reelection rates are rarely responsive to public opinion of Congress. Even in years when congressional approval tanks, incumbent turnover holds steady.

For one, overall congressional approval numbers don't extrapolate well. Voters elect solely their own representatives, and their ballots aren't necessarily a referendum on the entire legislative body. Last May, when congressional approval was at 13 percent, Gallup found about 46 percent approved of the job their representative was doing. This April, the AP asked a similar question, and found that while just 16 percent approved of Congress, 39 percent said they would like to see their member reelected. Of those who are most politically engaged, that figure was 44 percent.

Also, in recent years districts have become "safer" for political parties due to redistricting, as you can see in the sliding graphic to the right.

What's becoming apparent now is that even the historically low approval of Congress during the government shutdown — Gallup had it as low as 9 percent — can't shake this incumbent advantage. House reelection rates, in most cycles, are higher than 90 percent, according to OpenSecrets. For the Senate, those numbers are only slightly lower.

The Senate may very well flip to the Republicans, over a handful of seats, but the majority of the faces in the chamber will be the same.