MONTOURSVILLE, Pa. — On a balmy spring evening President Trump returned to Pennsylvania two days after former Vice President Joe Biden held a rally in Philadelphia and one day ahead of a special election for the 12th Congressional District seat where Republican Fred Keller is expected to win handily.

Standing with Air Force One in the background and the foothills of the Allegheny Mountains framing the large, boisterous crowd, Trump’s visit emphasized he is unwilling to yield any ground to whoever his 2020 opponent may be in Pennsylvania, including Scranton native Biden.

“I am here for you!” he said to cheers. “I got to win this state, got to win Pennsylvania."

“I don’t know how the hell you lose this election,” he said after listing a low unemployment rate in the state, a strong economy, and a manufacturing sector that is growing.

Trump enters a different state than he won in 2016; it has a weakened Pennsylvania state party, smaller majorities in the state house, and a split congressional delegation with the most recent Quinnipiac polls here showing Biden ahead of him in a head-to-head matchup.

Keystone College professor Jeff Brauer warns that Hillary Clinton was showing very large double-digit leads over Trump in that same poll around the same time in the last cycle. “It is very early and Trump obviously hopes to defy those polls once again in 2020,” Brauer said.

“Trump's strong showing in northeastern Pennsylvania was critical to his Pennsylvania win in 2016 and surprised many pundits as Clinton has roots there,” Brauer said of Clinton not only being baptized in Scranton, but also spending every summer there with her family.

Angelo Martin was pretty pumped to attend his first Trump rally despite not voting for the president in 2016; the 22-year-old registered Republican said he voted for Hillary Clinton because of Trump’s demeanor.

“Honestly I thought he was a little crazy the way he talked, and because of that I did not think he would get anything done. Turns out I still don’t like his style but I am more than happy with his policy decisions,” said Martin, who listed the tax cuts, judicial picks, and how Trump has dealt with foreign policy as some of the president’s accomplishments.

“He has more than earned my vote for 2020,” said Martin, who traveled from Selinsgrove to attend the rally.

Ryan Brandt, an electrician and small businessman also from Selinsgrove, said he voted for Trump in 2016 and noted the president has yet to do anything to make him vote any other way in 2020.

The 37-year-old Brandt said his business is thriving under Trump and the tax cuts were part of helping him expand his business. “My billings have doubled in the last year, a lot of that has to do with the fact that my community is doing better because of new companies and homes being built,” he said.

In 2016, Trump won Pennsylvania, a state that had not gone for a Republican since 1988, by over-performing in the west and northeast in traditionally Democratic counties that had slowly been moving Republican since 1996, when President Bill Clinton peaked for the party by winning 28 of the state’s 67 counties.

By 2012 support in the state for a Democrat had eroded down to a 13-county win out of the 67 counties for President Barack Obama, so the trend was already in place ahead of the Trump–Clinton matchup in 2016.

Brauer said while it had almost always been seen as a political risk for a president to put his weight behind a special election, “Trump has continually defied political norms since announcing his candidacy and has thrived. In this case, it's good idea for him to return to Pennsylvania, a state vital to his 2016 election victory, and retest the waters of this popularity. It will be a chance to create enthusiasm early in the 2020 election cycle and reassure his voters."

Pennsylvania’s primary Tuesday should offer some clues as to where the Democratic Party is in the state. While Sen. Bob Casey and Gov. Tom Wolf ran up big numbers in Trump Country in last year’s midterm elections, with the suburbs providing a hint as to who might make or break the presidential contest, it is unclear whether suburban Republican voters will realign with the Democratic Party or come back home.

Experts suggest that all depends on how far Left the eventual Democratic nominee is forced to go or how much purity is demanded by an agitated primary base.

Ruth Moore, 60, was holding her 13-month-old granddaughter Addy to board the shuttle bus to attend the Trump rally. Moore said she happily voted for Trump in 2016; her sister Robin Beilman, 58, not so much.

“I didn’t vote for Hillary either; I just didn’t vote,” said Beilman, who works in a nearby factory making Pop-Tarts.

“At first I didn’t like how he conducted himself; I still always don’t, but what I have come to realize is that if you want to get tough things done, you don’t get them done by being nice,” she said.

Now Trump has earned her full support.

To offset the uncertainty of where suburban voters go in 2020, Trump is going to need to expand his base in order to win not just Pennsylvania, but also Michigan, Florida, and Wisconsin. He has to do that by earning votes from people such as Martin and Beilman, said G. Terry Madonna, a political science professor and pollster at Franklin and Marshall College .

“My best guess is, we are going to see a lot of rallies like the one we saw here tonight in Pennsylvania to remind his supporters of why they voted for him and to draw out higher numbers from their friends and neighbors who sat on the sidelines or voted Clinton or third party in 2020,” Madonna said.