May 15 (UPI) -- More midterm matchups will be set Tuesday in Democratic and Republican primaries in four more states -- Pennsylvania, Nebraska, Idaho, and Oregon.
Pennsylvania's outcome could represent the Democrats' best opportunity in the House for the fall. It also has a governor and U.S. Senate seat to defend.
Republican primaries for governor are on ballots in Idaho, Oregon and Nebraska, and Democrats are targeting key House and Senate seats.
Democrats could benefit in this key battleground state with a new congressional map, as well as open seats in races that will help predict the party's chances in November.
In Pennsylvania's 1st District, three Democrats are trying for a chance to unseat Republican incumbent Brian Fitzpatrick -- including Rachel Reddick, a 33-year-old Navy veteran who's the only woman running for the seat.
Reddick will challenge philanthropist Scott Wallace and environmentalist Steve Bacher.
Pennsylvania's 5th, 6th and 7th Districts, all Republican-held areas that Hillary Clinton won in 2016, have open seats.
In the 11th District, incumbent Rep. Lloyd Smucker faces another GOP challenger and county commissioner Doug McLinko faces incumbent Rep. Tom Marino in the 12th.
"He is strong & smart, loves Pennsylvania & loves our Country! Voted for Tax Cuts, unlike Bob Casey, who listened to Tax Hikers Pelosi and Schumer!" Trump tweeted.
Democratic Gov. Tom Wolf is also up for re-election and will face Tuesday's GOP winner, which include state Sen. Scott Wagner, attorney Laura Ellsworth and consultant Paul Mango.
Republican incumbent Sen. Deb Fischer will face a Democratic challenger in the fall -- possibly Jane Raybould, a Lincoln City Council member who experts believe would contend for the seat in November if she wins her party's primary Tuesday.
Democrats are also hoping to reclaim a House seat in the 2nd District, which includes heavily-populated Omaha. Republican Rep. Don Bacon may again be challenged by Democrat Brad Ashford, who he unseated in 2016.
Incumbent Democratic Gov. Kate Brown is favored to emerge Tuesday as her party's nominee in the fall. If she does, she will face the GOP primary winner from among state Rep. Knute Buehler, former Navy pilot Greg Wooldridge and entrepreneur Sam Carpenter.
Idaho's gubernatorial seat is wide open, as incumbent Gov. Butch Otter is not running for re-election.
Three GOP candidates are top contenders for the post, including Lt. Gov. Brad Little, Rep. Raul Labrador and real estate developer Tommy Ahlquist.
Barca said it would take a "herculean effort to piece together a winning campaign and would be further complicated given the prior endorsements by the Democratic Congressional Campaign Committee and a number of key allied groups."