Voters in OH and Kansas joined those in Missouri, Michigan and Washington state.
Trump also endorsed Kansas gubernatorial candidate Kris Kobach, and Tuesday's GOP gubernatorial primary results in the Sunflower State will be another test of how much GOP primary voters value Trump's endorsement.
Polls closed at 7 p.m. With most of the votes counted, the two candidates traded a lead of just a few hundred votes.
The 12th district, split between suburban Columbus, Ohio, and rural areas, has been represented by a Republican since the early 1980s.
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In the episode , Kim tried to arrange the annual family Christmas card photoshoot. Kourtney, 39, wrote: "Watching this fight actually gives me chills".
President Trump campaigned for Balderson, a 56-year-old state senator, this past weekend in an effort to energize the GOP base, but some Republicans anxious that the president's appearance could have had an adverse effect by motivating voters who don't like Trump to come out for O'Connor.
Tuesday's elections could provide a window into the direction of the Democratic Party as the 2020 presidential nominating contest gets underway and party leaders debate whether to embrace a more liberal platform in hopes of turning out voters who sat out the 2016 election or make a centrist turn to court moderates and Republicans who are alienated by Trump.
"I've worked in OH presidential and senate races for Republicans and the idea of #oh12 being a close race is sort of like hearing gravity is a regional phenomena", tweeted Republican strategist Stuart Stevens. Republicans now hold a two-seat majority in the Senate, while Democrats need to net 23 seats to take control of the House. The two candidates will face off again in November. Kobach was an immigration adviser to Trump's campaign in 2016 and vice chairman of Trump's commission to investigate voting fraud before the panel collapsed. Trump claimed House Democratic leader "Nancy Pelosi controls Danny O'Connor, whoever the hell that is".
On stage with Trump, Balderson called himself "someone who will fight for President Trump's economic agenda".
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But Canada has stood firm, with Foreign Minister Chrystia Freeland insisting it would defend human rights around the world. Ths image included the Arabic saying: "He who interferes with what doesn't concern him finds what doesn't please him".
O'Connor has dominated Balderson on the local airwaves.
Trump made his preference clear for Kobach.
"He is a fantastic guy who loves his State and our Country - he will be a GREAT Governor and has my full & total Endorsement!"
O'Connor and his Democratic allies railed against the tax plan, casting it as a giveaway for the rich that exacerbates federal deficits and threatens Medicare and Social Security.
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Though the Ordinary People filmmaker previously said he'd focus on directing when he stopped acting, he doesn't seem so sure now. Tucker's crime spree lasted more than 60 years. "To me, that was a wonderful character to play at this point in my life".
In Kansas' 3rd District, Bernie Sanders-backed labor lawyer Brent Welder is running in a six-way primary to take on Yoder. Bernie Sanders and NY congressional nominee Alexandria Ocasio-Cortez, who catapulted to fame when she defeated the No. 4 House Democrat in a June primary. He would join Tim Scott of SC as the only black Republican senators if he wins in November.