What you need to know about the Pa. primary election

HARRISBURG, Pa. (AP/WTXF) -- Pennsylvania voters have a lot to think about when they hit the polls for Tuesday's primary, including a hotly contested Republican primary for governor.

Also on the card are a five-way race for the Democratic nomination for lieutenant governor, a Republican primary to pick who will take on Democratic U.S. Sen. Bob Casey in the fall, House races in the wake of the major redistricting case and a host of open seats in the Legislature.

Polls are open from 7 a.m. to 8 p.m., and elections officials emphasize that the redistricting decision did not change where anyone in the state will be voting.

GOVERNOR

Democratic Gov. Tom Wolf is running for a second term and is uncontested in Tuesday's primary election. On Tuesday's Republican ballot for the nomination to challenge him in the November election are three people: Scott Wagner, a state senator from York County who has made millions in the waste-hauling industry; Paul Mango, a former health care systems consultant; and Laura Ellsworth, a commercial litigation attorney and former chairwoman of the Greater Pittsburgh Chamber of Commerce.

Both Mango and Ellsworth are first-time candidates from suburban Pittsburgh. Wagner is the party's endorsed candidate.

LIEUTENANT GOVERNOR

Lt. Gov. Mike Stack is fighting for another term in office after a first term in which he had a chilly relationship with Democratic Gov. Tom Wolf. Wolf last year ordered an investigation into the treatment of state employees, including state police troopers, by Stack and his wife and stripped Stack of state police protection. Stack later said his wife entered a residential treatment facility for a mental health issue.

Stack, a former Philadelphia state senator, has four Democratic challengers.

They are Nina Ahmad, a former deputy mayor under Philadelphia Mayor Jim Kenney and a former president of the Philadelphia chapter of the National Organization for Women; Chester County Commissioner Kathi Cozzone; Montgomery County activist Ray Sosa; and John Fetterman, who ran unsuccessfully in 2016's U.S. Senate primary and is something of a national media darling for his efforts to revive the down-on-its-luck steel town of Braddock, where he is mayor.

Four Republicans are running in the primary. They are Jeff Bartos, a real estate investor from suburban Philadelphia who is campaigning with Wagner; Diana Irey Vaughan, a Washington County commissioner who has run previously for Congress and state treasurer and who is campaigning with Mango; Kathy Coder, a Republican State Committee member from Allegheny County; and Marguerite "Peg" Luksik, a longtime conservative activist from Cambria County who has run twice for governor and once for U.S. Senate.

U.S. SENATE

Democratic U.S. Sen. Bob Casey is running for a third six-year term in office and the son of the late former governor is uncontested in the primary. Casey is one of 10 Democratic senators running for re-election in states won by President Donald Trump in the 2016 election. That has put a target on his back for Republicans.

On Tuesday's Republican ballot is four-term U.S. Rep. Lou Barletta, the former mayor of Hazleton in northeastern Pennsylvania, and five-term state Rep. Jim Christiana of Beaver County.

Barletta has been running for months as the presumptive Republican nominee: He is endorsed by the state Republican Party and backed by President Donald Trump. The race has been sleepy to this point: Barely any outside money has crept into Pennsylvania to help a candidate after Pennsylvania saw a record-breaking $180 million U.S. Senate race in 2016.

U.S. HOUSE

Pennsylvania is hosting 21 contested primary elections on Tuesday's ballots for the state's 18 U.S. House seats. All told, there are 84 candidates on primary ballots, the most since 1984, and there are seven open seats, the most since 1976, when Pennsylvania had 25 seats in the U.S. House.

Six incumbents -- Democrats Mike Doyle of Pittsburgh and Brendan Boyle and Dwight Evans of Philadelphia and Republicans Brian Fitzpatrick of Bucks County, Tom Marino of Lycoming County and Lloyd Smucker of Lancaster County -- are facing primary challenges.

Democrats are settling primary races to challenge five Republican incumbents and to run in November's general election for five open seats. Republicans are settling primary races to challenge one Democratic incumbent and to run in November's general election for four open seats.

Republicans held a 13-5 advantage in the delegation after the 2016 election. However, since then, three Republicans have resigned, leaving two seats vacant for now and another filled in a special election by Democrat Conor Lamb. In February, the state Supreme Court redrew the districts after ruling in a gerrymandering case that Republicans who controlled state government in 2011 had unconstitutionally drawn the districts to benefit their party's candidates.

Under the new boundaries, Democrats expect to flip two seats while three others are considered toss ups.

STATE LEGISLATURE

Democrats hope the primary will be a step toward getting back a majority in either chamber, but it's unlikely this year they will get close. Republicans currently control the House, 121-82, and the Senate, 36-14.

The high-profile contests in the primary are vacancies in the large parts of Pennsylvania where one party or the other has an overwhelming majority of voters.

There are also three special elections on Tuesday to fill vacancies created when three House members left early to take other jobs: Rep. Brandon Neuman, D-Washington; Rep. Scott Petri, R-Bucks; and Rep. Matt Baker, R-Bradford.

VOTER INFORMATION & RESOURCES

You can check election results as they come in below. App users click here to see results.