We now have the third Senate retirement of this term, and it’s a doozy.  Tom Harkin, one of the most liberal members in the upper chamber, won’t seek a sixth term of the Senate in 2014:

U.S. Sen. Tom Harkin will not seek re-election in 2014, the Iowa Democrat said Saturday.

The 73-year-old Harkin told The Associated Press in an interview, “It’s just time to step aside,” noting that by the time he would finish a sixth term, he would be 81.

Harkin said the move also would allow a new generation of Democrats to seek higher office.

That’s debatable.  Iowa hasn’t exactly shifted to the left during Harkin’s tenure, and his status as incumbent was probably the best hope Democrats had in keeping the seat.  Harkin already had almost $3 million in his campaign fund and may have been unbeatable, and certainly no Democrat before this would have considered running for the seat.

Now, Democrats will have to bloody themselves in a primary the same as Republicans.  They have two former governors who might give it a run: Chet Culver and Tom Vilsack, currently the Secretary of Agriculture in the Obama administration. That may not help Vilsack, especially if Iowans want to look in a more independent direction as the Obama administration shifts significantly leftward in the next two years, and gun control will be a big issue in Iowa for anyone connected to the White House now.

The most prominent Republicans are Rep. Steve King and Governor Terry Branstad.  Branstad is serving his fifth term as governor (the first four were consecutive between 1983-1999). King won his sixth term in the House in a newly-redistricted IA-04, beating Vilsack’s wife Christie by eight points.  Neither might have been interested in challenging Harkin, but with his retirement, both may become very interested.  Branstad has won a number of statewide races, and it might make more sense for him to forgo a sixth term as governor to aim for the US Senate.  King has a relatively high national profile in the Tea Party movement, and might decide to risk losing his House seat to move up to the Senate, and he could build a significant grassroots organization to help.

That’s now two Democratic retirements (Jay Rockefeller, WV) to one Republican (Saxby Chambliss, GA).  Republicans have at least a good chance of winning all three in a second-term midterm contest.  We’ll see if any other red state Senators feel like hitting the retirement trail in the next two years.

Update: A commenter tells me that Chect Culver isn’t related to the Culver family that founded the fast-food chain.  Since I couldn’t find a good reference one way or the other, I’ve removed that from the post above, and apologize for the error.