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.
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.
Two primaries in Michigan marked a turnabout from several years of widely heralded contests in which right-flank candidates have tried - sometimes successfully - to unseat Republican incumbents they perceive as not being conservative enough.
Bentivolio did not survive, but in the 3rd Congressional District in the southwest part of the state, Rep. Justin Amash, who has challenged the GOP leadership, led Brian Ellis, a 53-year-old Grand Rapids businessman who owns an investment advisory firm and serves on the school board.
Amash is popular among libertarians for his challenges to the National Security Agency's surveillance of Americans.
Five of Missouri's eight House members were expected to easily dispatch their underfunded challengers.
In Washington state, voters considered 12 candidates vying to replace 10-term Rep. Doc Hastings, a Republican who is retiring. The two candidates who collect the most mail-in ballots advance to the general election, setting up what could be a Republican-versus-Republican contest in the heavily GOP district in central Washington.