Iowa’s June 3 primary election will include a number of contested races….

U.S. SENATE

Five Republicans are vying for the nomination to face Democrat Bruce Braley in a race drawing national attention as the GOP seeks the six seats needed to capture the majority. State Sen. Joni Ernst of Red Oak has emerged as the front-runner in a field that includes former Reliant Energy CEO Mark Jacobs of West Des Moines.

Ernst’s two TV ads have raised eyebrows, dollars and endorsements. In the first ad, she recalled castrating hogs as a farm kid. In the second, the Iowa National Guard colonel fires a handgun. Jacobs has recently begun attacking Ernst for missing votes in the Iowa Senate this year.

Sioux City college professor Sami Clovis has a loyal following, though polls indicate he trails Ernst and Jacobs, as do former U.S. Attorney Matt Whitaker of Ankeny and Ames businessman Scott Schaben. A candidate must win at least 35 percent of the vote to avoid a nominating convention.

U.S. HOUSE, 1ST DISTRICT

Much of the action is among a crowded Democratic field vying to succeed four-term U.S. Rep. Bruce Braley. State Rep. Patrick Murphy of Dubuque has garnered most of the labor-union endorsements in Iowa’s most industrial congressional district. That may be enough to top Iowa Utilities Board member and former state Sen. Swati Dandekar of Cedar Rapids, Cedar Rapids City Council member Monica Vernon and state Rep. Anesa Kajtazovic.

Dubuque businessman Ron Blum leads a Republican field that includes Cedar Rapids businessman Steve Rathje, who has run unsuccessfully for U.S. Senate and House, and Marshalltown lawyer Gail Boliver.

U.S. HOUSE, 2ND DISTRICT

Four-term Democrat Dave Loebsack of Iowa City has twice fought off Republican Mariannette Miller-Meeks of Ottumwa. Finding out whether the third time is a charm may depend on turnout in this Democratic-leaning southeast Iowa district. Miller-Meeks, former director of the Iowa Department of Public Health, leads the GOP field that also includes state Rep. Matthew Lofgren and Eddyville research technician Matthew Waldren.

The largely rural district includes Democratic-leaning Johnson County, but also counties in southeast Iowa where unemployment has remained above the state average.

U.S. HOUSE, 3RD DISTRICT

Iowa’s 3rd District race has had more drama than any other so far, as 10-year incumbent Rep. Tom Latham’s announcement that he would retire prompted a large primary field. The six Republican candidates will almost certainly force a nominating convention, the results of which will give a strong indication of how competitive this district will be come November. The district includes the Des Moines metro area and rural southwest Iowa.

Iowa Renewable Fuels Association President Monte Shaw and David Young, the former chief of staff to U.S. Sen. Charles Grassley, are more popular in the GOP’s establishment wing. Bob Cramer, who heads a Christian conservative group, Secretary of State Matt Schultz and state Sen. Brad Zaun are considered more conservative, with a following among the tea party movement.

Des Moines Republican activist and former state Rep. Joe Grandanette is also running. The winner will face Ackworth Democrat Staci Appel, a former state senator.

LEGISLATURE

Before the playing field is set for Iowa’s closely divided Legislature, majority House Republicans will have to sort out eight primaries and majority Senate Democrats will have to settle six. A factor in whether the GOP’s current 53-47 control of the House will change is the number of uncontested seats. Republicans haven’t fielded a candidate in 32 of the seats held by Democrats. Likewise, Democrats are not contesting 26 of the 53 districts controlled by Republicans.

It’s similar in the Senate, where Democrats hold a 26-24 edge. Only 11 of the 25 seats on the ballot have the makings of two-party contest in the fall. Eight Democratic seats are uncontested, as are six Republican-held seats.

Candidates can be nominated at special party conventions.