Four states will host primary elections Tuesday, setting up matchups for several key races this fall. 

Pennsylvania, Idaho and Nebraska all have House primaries to watch. And the Keystone State’s new congressional lines will be tested for the first time. The state’s Supreme Court tossed out the old map earlier this year, deeming it an unconstitutional partisan gerrymander. 

Oregon votes by mail and ballots have to be in by Tuesday. The Beaver State is not hosting any marquee House or Senate races this cycle, so much of the attention will be on the other three states. 

Here are four things to watch for in Tuesday’s primaries:

1. Keystone State contests 

Democrats view Pennsylvania as a major piece of their plan to flip the 23 seats necessary to win back the House. The new congressional boundaries improved their chances in some of their key targets.

Perhaps their best pickup opportunity is the new 5th District, vacated by GOP Rep. Patrick Meehan, who resigned last month amid allegations of sexual harassment. A crowded primary is underway on the Democratic side, and the winner will be in a strong position in a seat that Hillary Clinton would have carried by 28 points in 2016. Inside Elections with Nathan L. Gonzales rates the race Likely Democratic. 

The new 7th District is one of seven open seats in Pennsylvania, and another target that improved for Democrats under the new map (and after GOP incumbent Charlie Dent announced he was leaving Congress). The crowded primary on the Democratic side features Northampton County District Attorney  John Morganelli, former Allentown City Solicitor Susan Wild and pastor Greg Edwards. Morganelli has drawn heat from liberal groups for his stances on abortion and immigration. Ex-Olympian Marty Nothstein and former Lehigh County Commissioner Dean Browning are competing for the GOP nod. Inside Elections rates the race Tilts Democratic. 

A tougher target for Democrats but still within reach is Pennsylvania’s 1st District, held by GOP Rep. Brian Fitzpatrick. The Democratic primary in the Tilts Republican race features Navy veteran Rachel Reddick going up against philanthropist Scott Wallace, who has vastly outspent her on the airwaves. Fitzpatrick has drawn a primary challenger from the right in former Bucks County prosecutor Dean Malik.

And he’s not the only House Republican facing a primary. Freshman Rep. Lloyd K. Smucker squares off against his second cousin Chet Beiler in the new 11th District, which shifted more to the right under the new lines. Smucker is expected to win — he defeated Beiler in the open-seat GOP primary two years ago. 

A number of open seats in Pennsylvania are safe for either party. So the winners of those primaries will be in strong positions heading into November. Polls close at 8 p.m. Eastern time Tuesday. Watch: 3 Things to Watch in Pennsylvania’s Primaries

2. Nebraska’s 2nd District 

The Democratic primary in Nebraska’s 2nd District has not attracted the same attention as other intraparty fights, partly because the candidates here have not been attacking each other. Former Democratic Rep. Brad Ashford is eyeing a rematch against GOP Rep. Don Bacon, who unseated him by 1 point two years ago. 

But first, he has to win Tuesday’s primary against Kara Eastman, a nonprofit executive. Eastman has noted that she is the only lifelong Democrat in the race, saying the party is ready for new types of candidates. The first-time hopeful supports “Medicare-for-all” legislation and abortion rights. Some outside groups, including the Progressive Change Campaign Committee, have backed Eastman, but she’s expressed disappointment more pro-abortion rights groups have not supported her campaign.

Ashford, a onetime state legislator and former Republican, won his first House term in 2014 against a flawed GOP incumbent. He’s been added to the Democratic Congressional Campaign Committee’s Red to Blue program for promising challengers. Groups backing him include the Blue Dog and New Democrats coalitions. Inside Elections rates the 2nd District race Tilts Republican. Polls in Nebraska close at 8 p.m. in the Central time zone and 7 p.m. in the Mountain time zone. 

3. Idaho’s 1st District

Rep. Raúl R. Labrador’s decision to run for governor opened up his 1st District seat, which President Donald Trump carried by 38 points. Labrador has endorsed former state Sen. Russ Fulcher to succeed him.

Fulcher had been running for governor, but switched to the House race after Labrador launched his own gubernatorial bid. He worked in tech before becoming a state legislator. He has also been endorsed by the conservative Club for Growth PAC.

Fulcher has raised the most of his Republican opponents, raising $436,000, according to Federal Election Commission documents. David Leroy, a former Idaho lieutenant governor and attorney general, raised $332,000. State Rep. Luke Malek brought in $249,000, while conservative author Michael Snyder, who has been endorsed by Kentucky GOP Sen. Rand Paul, raised $128,000.

The GOP primary winner will be a heavy favorite in November. Inside Elections rates the race Solid Republican. Most polls close by 8 p.m. Mountain time.

4. Senate challengers 

Two Senate matchups will also be set after Tuesday.

Pennsylvania GOP Rep. Lou Barletta appears poised to win the Republican nomination to take on Democratic incumbent Bob Casey this fall. Barletta was an early Trump ally, and the president recorded a robocall for him ahead of Tuesday’s primary, according to Politico.

Barletta has spent $2 million so far, including $503,000 in the first three and a half weeks of April alone, according to his pre-primary FEC report. His primary challenger, state Rep. Jim Christiana, has spent a total of $262,000, including $36,000 during the pre-primary period. 

Trump carried the Keystone State by less than a point in 2016, making Casey among the more vulnerable Democratic incumbents up for re-election. But Democrats are confident he’s in a strong position. Casey has more than $10 million in his campaign coffers — the highest by any Senate candidate in the state’s history, according to his campaign. 

In Nebraska, GOP Sen. Deb Fischer is not facing a major primary challenge — something that might have seemed unlikely late last year, when White House chief strategist Steve Bannon said he wanted to back primary challengers to every GOP incumbent up for re-election in 2018 except Texas Sen. Ted Cruz. But seven months later, Bannon is banished from the White House, and Fischer is in no danger of losing her primary. 

Lincoln City Council Member Jane Raybould is the apparent front-runner in the Democratic primary. She has raised $804,000 so far, 16 times more than the next closest Democrat. But she trails Fischer in cash on hand. Raybould has $310,000 in the bank at April 25 compared to Fischer’s $2.6 million. 

Raybould, who faces an uphill battle in a state the president carried by 26 points, has been focusing her recent messaging on how Trump’s tariffs could hurt farmers in the Cornhusker State. Inside Elections rates the Senate race Solid Republican.