Attention will shift from the campaign trail to the voting booths as Pennsylvanians cast ballots on presidential primary contests and races for Congress and state offices on Tuesday.
Terry Madonna, director of the Franklin & Marshall College Poll, said candidates hosting last-ditch events from Pittsburgh to Philadelphia on Monday wanted to woo delegates as much as voters.
Most mathematical delegate estimates show Republican front-runner Donald Trump, who spoke to thousands in Wilkes-Barre on Monday, won't win the party's nomination outright. Pennsylvania boasts 54 potentially unbound delegates, meaning they can vote for any contender in a contested convention regardless of who wins the state’s popular vote.
“So a delegate could get elected saying ‘I’ll vote for Trump or I’ll vote for Cruz or I’ll vote for Kasich’ but he or she is free to do whatever they want,” he said.
Pennsylvania's primary matters for the first time in decades, Madonna said, with one notable exception: Democratic contenders camped out for nearly five weeks in 2008 when Barack Obama ultimately beat Hillary Clinton by about 200,000 votes, or 9 percent.
"They literally were here non-stop," Madonna said. "It was probably Hillary Clinton's last stand."
Welding student Ty Edmunds, 18, of Mt. Pleasant drove out to Westmoreland County Community College in Youngwood on Monday to hear Clinton stump about gun control, affordable education, raising the minimum wage and women's rights.
"I think that she sort of sees the plan the whole way through, whereas Bernie's looking for something that may not help the economy, like raising the minimum wage to $15," he said. "While Trump -- he's just off his rocker."
Republican contenders Texas Sen. Ted Cruz and Ohio Gov. John Kasich announced apparent coordinated strategies Monday to combat Trump in upcoming primaries in Indiana, New Mexico and Oregon.
“I think that’s a joke to be honest," said high school senior and Trump supporter Zack Zurcher, of Oakdale. "I feel like the Republicans should be uniting behind the front-runner instead of trying to destroy him, because I feel like if they do that it’s just going to make it easier for Hillary to get in office.”
Like Zurcher, Michelle Ritchey of Mt. Lebanon attended Kasich's town hall at Montour High School in Robinson on Monday. Standing with her 10 year old, Ritchey said she worries most about debt and national security.
"That’s a burden I don’t want to pass on to my children," she said.
Vermont Sen. Bernie Sanders kicked off Pittsburgh's election season nearly one month ago, drawing an estimated 8,500 Downtown. He held a more intimate, optimistic affair for a few hundred at the University of Pittsburgh's Fitzgerald Fieldhouse on Monday.
Mark Brown, 41, who attended Sanders' latest rally, said he’s been volunteering with the campaign for about a year.
"At the start nobody knew who Bernie was, now everybody knows who Bernie is," Brown said. "We go out and all we hear is, 'Go Bernie!' He’s caught on in Pittsburgh.”
First time voter, 19-year-old David Wovchko, of Crafton attended Cruz's first Pittsburgh-area event on Saturday. Cruz is most in line with his “radical libertarian” views, Wovchko said.
“In this case, Ted Cruz has a really good record for standing for free markets and that’s very valuable to me,” he said. “(He) can move us closer to a world I’d like to see.”
Democrat Pete Pamula, 66, of the South Side said he's enjoying the candidates' nearly constant back-and-forth.
"Both sides are energized, so this is a good situation," he said. "I hope the debate goes all the way up to the convention floor."
Tuesday's primary also decides contests for party nominees for U.S. Senate, 18 U.S. House seats, state attorney general and 228 state legislative seats.
A four-way Democratic U.S. Senate primary has come down to Katie McGinty and Joe Sestak for the nod to challenge Republican incumbent Pat Toomey in November. Braddock Mayor John Fetterman is also a contender. Three Democrats and two Republicans are running to succeed Democratic Attorney General Kathleen Kane.
Polls are open from 7 a.m. to 8 p.m.
90.5 WESA reporters Virginia Alvino, Noah Brode, Sarah Schneider and Sarah Kovash contributed to this report, as did the Associated Press.