Iowans will elect 25 state senators today. Those races have attracted far less attention than this year’s Iowa House races, because Republicans have a lopsided 32-18 majority in the upper chamber and only a 53-47 advantage in the House.

Nevertheless, it’s important to keep an eye on the Senate races, because this year’s outcome will influence Democratic prospects under the new map coming in 2021.

This overview covers five districts where both parties are spending six-figure amounts, seven districts where Republicans spent a significant amount, and four more districts where the results could shed light on political trends in various parts of the state, even though neither Democrats nor Republicans targeted the race.

Democrats continue to land solid candidates for Iowa Senate seats, despite the GOP’s 32-18 majority in the upper chamber.

This week Warren Varley, a farmer and attorney, made his campaign official in Senate district 10, where GOP incumbent Jake Chapman has not faced a serious challenge before.

State legislator retirements are typically a problem for the party out of power. Members of the majority can chair committees, drive the agenda, and get plenty of attention from lobbyists. Life in the minority caucus is much less satisfying.

Although Iowa House Republicans enjoy a 59-41 majority, four GOP representatives have already confirmed plans to step down this year, with more retirements likely before the March 16 filing deadline. When incumbents don’t seek re-election, party leaders sometimes must spend more resources defending open seats, leaving less money available for top and especially second-tier targets.