Last Updated Aug 6, 2014 7:00 AM EDT
Sen. Pat Roberts fended off an aggressive challenger Tuesday in the Kansas Republican primary, dealing another blow to a national tea party movement that has targeted longtime Washington incumbents.
Milton Wolf, 43, a Leawood radiologist making his first run for public office, failed to pull the upset in the race against Roberts, 78, whose political dates to the late 1960s, when he was a congressional aide.
With 100 percent of the precincts reporting, Roberts had 48 percent to Wolf's 41 percent while two other candidates combined for 11 percent of the vote.
After surviving the primary, Roberts is a huge favorite to win his fourth, six-year term in November. Republicans enjoy a nearly 20 percentage-point advantage among registered voters and have won every U.S. Senate race in the past 80 years.
Wolf has said he is a distant relative of President Barack Obama but stresses his strong opposition to the Democrat's signature health care overhaul. He said his mother and Obama's grandmother were cousins, describing himself as a second cousin, once removed, of the president. He acknowledges that they did not meet until after Obama was elected.
Later, he attacked Roberts as a career politician out-of-touch with Kansas.
Roberts overcame an early-July gaffe in a radio interview about the rented space in a Dodge City home he lists as his official residence and attacked Wolf relentlessly over questionable postings of graphic X-ray images on a personal Facebook page in 2010.
Wolf had the backing of national tea party groups that were energized by House Majority Leader Eric Cantor's loss in Virginia's GOP primary in June.
Kansas, famous for sending moderate Republicans to Congress, holds Tuesday's marquee contest..
The GOP establishment blames the tea party for costing it Senate control in 2010 and 2012 as outside candidates stumbled in the general election. Republicans need to net six seats to regain the Senate, and the party has taken no chances this election cycle, putting its full force behind incumbents and mainstream candidates.
Tuesday also offered competitive primaries in Michigan, Missouri and Washington state. Businessman Dave Trott easily defeated Rep. Kerry Bentivolio, 66 to 34 percent, in Michigan's 11th Congressional District, a reversal of the recent political order of tea partyers aiming to knock out an establishment favorite.
Bentivolio was often described as the "accidental" congressman, as he was elected in 2012 when former Rep. Thaddeus McCotter turned in fraudulent voter signatures for a ballot spot. Bentivolio is the third House incumbent to lose in the primary, joining Republican Reps. Eric Cantor of Virginia and Ralph Hall of Texas on the House casualty list.
Two-term Rep. Tim Huelskamp, a Republican who has frustrated GOP leadership and his rural constituents over his votes against the farm bill, was locked in a close race with Alan LaPolice, a farmer and educator. Huelskamp held a 53 percent to 47 percent lead with 18 percent of precincts reporting.
The four-state primary day launches a crowded stretch with Tennessee on Thursday, Hawaii on Saturday and Connecticut, Minnesota and Wisconsin next week. By month's end, voters will decide the Republican Senate nominee in a competitive race against Sen. Mark Begich in Alaska and the Democratic primary between Hawaii Sen. Brian Schatz and Rep. Colleen Hanabusa.
So far this year, the Senate's establishment is on a roll, with incumbents already prevailing in Texas, Kentucky, South Carolina and Mississippi, though it took six-term Sen. Thad Cochran two tries before defeating Chris McDaniel, who is challenging the outcome.
In one of the fiercest House GOP primaries, two-term Kansas Rep. Mike Pompeo defeated Todd Tiahrt, who served eight terms in the House and was trying to return to Washington.
In Michigan, six-term Sen. Carl Levin, a Democrat, is not seeking re-election. Republican Terri Lynn Land will face Democratic Rep. Gary Peters in a race considered a toss-up.
Dave Trott contributed almost $2.5 million of his own money to his campaign for Congress, and it paid off as he beat first-term Michigan Republican Rep. Kerry Bentivolio.
Investment adviser Brian Ellis didn't get the same return on his investment. He lent his campaign $1 million, but was unable to topple Rep. Justin Amash, R-Mich., who has sparred often with Republican leaders since his election in the 2010 tea party wave.
Meanwhile, Rep. John Dingell, D-Mich., who has been in Congress for a record 58 years, is retiring. But his wife, Debbie, won her primary bid to replace her husband on Tuesday and is expected to extend the Dingell dynasty come November.
In Washington state, a dozen people - eight Republicans, two independents and two Democrats - sought to replace retiring Republican Rep. Doc Hastings in a central Washington district. The state has a top-two primary system, meaning that the top two vote-getters advance to Election Day regardless of party affiliation.
The winners? Republicans Clint Didier, a former NFL star who won two Super Bowl rings with the Washington Redskins and campaigned as a tea party candidate, and Dan Newhouse, a former state lawmaker and agriculture director.
The district hasn't elected a Democrat since 1992, and Hastings generally cruised to re-election victory after first winning the seat in 1994. It's home to farms that grow much of the nation's crop of apples, cherries, grapes and hops to flavor beer, as well as the giant Hanford Nuclear Reservation, a federal installation that hold the nation's largest volume of nuclear waste.
All of the Washington state's other incumbent members of the U.S. House advanced Tuesday, when about 40 percent of Washington's registered voters were expected to cast ballots in the vote-by-mail election.
Tuesday's primary was the first of three election days this week. Voters in Tennessee will cast ballots Thursday, when GOP Sen. Lamar Alexander faces a challenge in the GOP primary from tea party-backed state lawmaker Joe Carr.
On Saturday, Democratic Sen. Brian Schatz seeks his party's nomination in Hawaii against Rep. Colleen Hanabusa, as they both seek to complete the term of the late Sen. Daniel Inouye, who died in 2012.