Six-term Sen. Thad Cochran and tea party candidate Chris McDaniel are making their final pushes today in the Magnolia State. The Post's Robert Costa and Jeff Simon are on the ground and report. (Jeff Simon/The Washington Post)

The two most vulnerable members of Congress on Tuesday share something in common: they're old, and they've been here for a very long time.

Sen. Thad Cochran (R-Miss.) and Rep. Charles Rangel (D-N.Y.) both find their careers on the line as voters head to the polls today for the Mississippi primary runoff and the New York primary. And the two of them just happen to comprise half of the four longest-serving members of Congress, at more than four decades apiece.

They're also fighting for their political lives a few weeks after Congress's oldest member, 91-year-old Rep. Ralph Hall (R-Tex.), lost a primary runoff.

But is all that really a coincidence? Or are primary voters picking on old folks?

Indeed, it seems more the latter. The members of Congress who have lost primaries in recent years have definitely skewed older than your average congressman or senator.

The average age of the Senate is in the low 60s, according to the Congressional Research Service, but the average age of the five senators who have lost primaries since 2006 is 71 years old.

The average age of the House is 57 years old, but the average congressman or -woman who loses a primary is about 61 years old on Election Day.

The same holds true when you look at length of service.

While the average member of the House has served nine years, the average primary loser has served 13.6 years. And while the average senator has served 10.2 years, the average length of service for the five senators who lost primaries in recent years is more than twice that much: 22 years.


Should Cochran and/or Rangel both lose Tuesday and be kicked out of Congress, those numbers would tick up even more. If it were Cochran, the average senator who lost a primary would have served a quarter century -- more than four terms.

To put that in perspective, only 12 current senators have even served that long.

Now, just because older members of Congress are losing primaries doesn't mean they are losing because they're old. Indeed, there are plenty of other factors at work here, including:

  1. The fact that many older members have coasted to reelection for years before someone mounted a serious primary challenge. This is definitely the case with Rangel and Cochran, and it can leave a member who was once a solid campaigner out of practice.
  2. Spending more time in Congress means you have more of a record and more votes that could potentially alienate people. You can bet there are plenty of members who wished they never had to cast votes on the TARP bailout, Obamacare, cap and trade, etc., and each such vote can earn you enemies.
  3. Campaigning is a grueling thing to do, and it's just much harder when you're getting on in years.

The first of these seems to carry particular weight. That's because, while members who have lost primaries are older, those who have lost in the general election don't have the same distinction. In the House, the average general election loser has served 8.5 years (close to the Congress-wide average of 9.1 years of service) and in the Senate, the average general election loser has served 12.9 years (again, closer to the average of 10.2 years for all senators).

In primaries, it seems, there are just more old members getting caught off-guard after years or even decades of limited campaigning. In the general election, that's less likely to happen because the vulnerable members know who they are at all times and have to constantly defend themselves.

But there was also a time when being old and having been in Congress meant seniority and clout. Today, in the post-earmark era, those arguments don't carry as much weight, and serving in Congress for decades isn't quite the feather-in-the-cap that it once was.

Cochran and Rangel could find that out the hard way today.