JEFFERSON CITY, Mo. — Congressman Todd Akin Tuesday won a hard-fought Republican primary for the right to challenge Democratic U.S. Sen. Claire McCaskill.

Akin on Tuesday topped businessman John Brunner and former state Treasurer Sarah Steelman in a primary in which all three leading candidates portrayed themselves as the top conservative choice.

McCaskill was unopposed in the Democratic primary.

Primary elections were being held in four states Tuesday. The Missouri race figured to have the greatest national significance: The GOP needs to net four seats from Democrats to gain control of the Senate, and Republicans viewed McCaskill as among their top targets this year.

Other races included:

• Michigan Republicans selected former U.S. Rep. Pete Hoekstra to take on Democratic U.S. Sen. Debbie Stabenow in November. Hoekstra easily outpaced his nearest challenger, Clark Durant, overcoming a late push by Durant that included sharp attacks on his conservative record and cast him as a Washington insider. Hoekstra will enter his race against Stabenow as the underdog. Stabenow, chairwoman of the Senate agriculture committee, is seeking a third term and has enjoyed a steady lead in polls.

• Missouri also featured a showdown between two of the state's most prominent Democratic families. U.S. Reps. Russ Carnahan and William Lacy Clay vied for a St. Louis-area seat in a race brought on by congressional redistricting.

• Republican primaries in Kansas could determine whether a conservative bloc takes control of the state Legislature.

In the Missouri Senate race, former Alaska Gov. Sarah Palin was dogged in her support of Steelman, a former state treasurer. The 2008 Republican vice presidential nominee has appeared in television and radio ads and campaigned with Steelman at a series of events.

Steelman, 54, has said she hopes to capitalize on the momentum of Ted Cruz, the Republican nominee for the Senate in Texas. He rode strong tea party support — and a timely boost from Palin — to an upset victory in that state's Senate primary last week.

Former Arkansas Gov. Mike Huckabee backed Akin, 65, who has also billed himself as a tea-party supporter and has a strong conservative voting record in Congress. But both Steelman and Brunner have sought to use that experience against him, portraying themselves as outsiders.

Brunner, 60, is a former CEO and chairman of Vi-Jon Inc., a health-care-products manufacturer. He has spent more than $7.5 million of his own money and stops short of calling himself a tea-party candidate, but he has the backing of FreedomWorks, a national tea-party group.

Polls indicate that any of the three would stand a good chance of defeating McCaskill. She took the unusual step of airing television ads targeting all three, a tactic that reflected the uncertain nature of the GOP primary.

NBA stars joining

Obama fundraiser

WASHINGTON — President Obama is joining NBA legend Michael Jordan and an array of basketball stars to raise money for his re-election campaign later this month.

The Obama campaign is planning a fundraising "shoot-around" and dinner in New York on Aug. 22 featuring several NBA stars, including Carmelo Anthony of the New York Knicks, Rajon Rondo of the Boston Celtics, John Wall of the Washington Wizards, and others. Jordan, who played for the Chicago Bulls, Obama's favorite NBA team, and NBA Commissioner David Stern are co-hosting a $20,000-per person fundraising dinner with the president later in the day.

Obama to focus

campaign on Iowa

At a time when he usually races from state to state seeking votes, President Obama has decided to invest much of next week in a single place, Iowa, the one where it all began for him.

Obama's campaign announced on Tuesday that he would take a three-day bus tour through Iowa, joined part of the time by his wife, Michelle. Iowa has long held a special place in the Obama creation story as the state whose caucuses propelled him on his way to the Democratic nomination in 2008.

A cumulative average of polls collected by the website Real Clear Politics shows that his lead there has slipped to barely one percentage point, its lowest since December and within the margin of error, making it effectively a tie with Mitt Romney.

Still, there has been so little recent polling in the state that it is hard to evaluate precisely where the race stands.

Iowa, with six electoral votes, is one of a handful of states considered crucial to putting together the 270 votes in the Electoral College needed to win the presidency on Nov. 6.

Obama will arrive in Iowa on Monday and hold campaign events in Council Bluffs and Boone.

Seattle Times news services