Thanks to Iowa’s non-partisan redistricting process, we have an unusually large number of competitive state legislative districts. In any given general election, depending on candidate recruitment, between one dozen and two dozen of the 100 Iowa House districts could be up for grabs. Democrats and Republicans spend big money on a much smaller number of districts; this year, only seven Iowa House races involved a large amount of television advertising. But the parties and candidates invest in direct mail and/or radio commercials in many more places than that.

Republicans go into election day favored to hold their Iowa House majority, which now stands at 53 seats to 47. Carolyn Fiddler has pegged seven “districts to watch” at her Statehouse Action blog, and in September, the Des Moines Register’s Jason Noble discussed five districts he viewed as “key to Iowa House chamber control.” I see the playing field as much larger.

Follow me after the jump to review 20 Iowa House seats that will determine control of the chamber for the next two years.

Caveat: most years, there’s at least one shocking result in an Iowa House district neither party had their eye on. I’m thinking about Tami Weincek defeating a longtime Democratic incumbent in Waterloo in 2006, Kent Sorenson defeating a Democratic incumbent in Warren County in 2008, three Democratic state representatives who had run unopposed in 2008 losing in 2010, and Democrat Daniel Lundby taking out the seemingly safe Republican Nick Wagner in the Linn County suburbs in 2012. Wagner had run unopposed in the previous election.

So, while I don’t expect any of the “favored” seats discussed below to change hands, I would not rule out a surprise or two. That would be excellent news for the stealth challenger’s party.

With less than two weeks remaining before June 3, interest groups with a preference in competitive primaries have presumably made their views known by now. On the Democratic side, labor unions are most likely to get involved in primaries, so I wanted to compile in one place the full list of candidates in competitive Democratic races who have been endorsed by one or more organized labor group. None of the Democrats seeking statewide office in Iowa this year has a primary opponent, and I’ve omitted county-level races. The list below includes candidates running for Congress in the first district and seeking various Iowa House and Senate seats.

I will update this post as needed if I learn of other labor union endorsements. Note that many other Democratic candidates already have or will have organized labor’s official support for the general election campaign. Blog for Iowa posted all of the Iowa Federation of Labor AFL-CIO’s endorsements for 2014 here. A complete list of candidates who will appear on primary ballots is on this page of the Iowa Secretary of State’s website.