Donald Trump still owns the circus-tent vibe four years after he first tested it successfully in Pennsylvania. But his second tour of MAGA arena shows may not be enough to do the trick again in a commonwealth where Democrats have wised up and pulled on their combat boots.

Democrats are flooding the electoral zone this year, no longer campaigning only in Pittsburgh and Philadelphia and expecting a magical win of the White House with a sweat-free investment.

Oh — and that presidential nominee of theirs? Joe Biden is no Hillary Clinton, which means mostly this: Joe is leaving none of the votes on the table that Clinton did. He is gunning for votes even in counties that Trump carried by huge margins. Counties that Clinton and Democrats in 2016 largely wrote off.

Biden and his surrogates are planning an apple-cart-full of visits across Pennsylvania in the final days of the race. It’s a staggering shift from 2016 when finding Clinton in Pennsylvania was as fruitless as finding Waldo on a blank page. Clinton lived and died by the idea that dialing up dollars and votes in Philadelphia and Pittsburgh was all that was needed to win this state, which once reliably voted for Democratic presidential candidates.

This strategic change was why I was hanging around a farm in Morrisville, Bucks County, on Monday, confused by the sounds of barking canines (an on-site doggie day care), the roar of highway traffic on Route 1, and visuals of hay bales, pumpkins, and a lectern. Jill Biden was due for one of her husband’s late-stage, pandemic-sensitive “rallies.” Chairs for maybe 60 people were spaced far apart with a small pumpkin beneath each one. This in a county that Trump did pretty well in four years earlier.

For all its lack of Trumpian, red-meat, ooh-gah, ooh-gah-ing, the Jill Biden appearance was exactly the display of effort we did not see from Clinton.

Democrats are awake in 2020. They are clawing even for votes in regions that Trump won handily.

The idea is that moderate Republicans and Democrats in Pennsylvania who chose Trump over Clinton when he seemed like a filterless political “outsider” are now exhausted. Perhaps Biden is the saner, safer choice now.

“Four years ago, I had to deal with a lot of anti-Hillary votes within the Democratic voters,” Bucks County Democratic Committee chairman John Cordisco told me ahead of Jill Biden’s speech at Snipes Farm and Education Center. "This time, you’re hearing from moderate Republicans in my county making clear that they can’t vote for this president.”

In another region altogether that was strong for Trump in 2016, southwestern and western Pennsylvania, native-son Lt. Gov. John Fetterman senses the same thing. It’s why he said he’s been pushing the Biden campaign to make appearances there that Clinton did not. So far, Trump has responded with rallies of his own.

“There is no sale necessary to get people on board to voting for Joe Biden the way there was for Clinton in ’16,” Fetterman said Thursday. “It has been a sea change. Because everybody’s seen what Donald Trump is capable of. This election is a referendum: Do you like the last four years, or do you want a change?”

» READ MORE: Biden courts swing voters in Pennsylvania while Trump rallies at the White House

When Clinton didn’t show up in 2016, it proved catastrophic.

Trump and his then-novel rallies motivated voters almost everywhere beyond big metro clusters in Pennsylvania. Clinton, who also struggled with high negative perceptions among even some Democratic voters, needed more — not less — engagement statewide.

» READ MORE: How Trump took Pennsylvania: Wins everywhere (almost) but the southeast

Biden appears to be angling for voters who resisted her but are ready for a break from Trump’s bellicosity and failures. Trump’s devastating mismanagement of the coronavirus pandemic is Exhibit A.

“Last time [Trump] had the base and the anti-Hillary votes that put him over the top," Cordisco said. "This time he doesn’t get an anti-Biden vote. It doesn’t exist. The focus is on him now. And it’s [members of] his party telling me it’s not where they can go.”

Democrats also are charging forth with a grassroots campaign to flip control of the state House and Senate from Republicans. It’s hoped that enthusiasm for those normally unsexy races flows up toward Biden, and vice versa.

They are doing this with a cadre of highly motivated Democratic activists and candidates who, largely backed by newly political women liberals, have rebuilt the flagging party from the municipal level on up since Trump’s election.

Biden’s final-stretch campaign events in Pennsylvania appear to have pushed Trump into a defensive crouch. Just days after the former vice president appeared in Erie, Trump held a rally there and admitted he had planned to blow off the place this year: “There was no way I was coming. I didn’t have to ... We had this thing won.”

Democrats are calling this strategy “shaving the margins” — getting enough votes back that Trump won four years ago in one county after another until you end up with a win.

“I’ve always said Pennsylvania is a margin play,” Fetterman said. “Republicans have such a hard time being elected statewide because they know it’s margins in small counties that can make up the difference.”

It’s smart that Biden is making moves into Bucks, even if a payoff does not seem obvious at first.

Unlike Delaware, Chester, and Montgomery Counties, which delivered for Clinton in titanic numbers in 2016, Trump held Clinton to a very slim margin in Bucks. He sent running-mate Mike Pence to a rally I covered in Bensalem in the campaign’s final days. Attendees told me beforehand some were unsure they could vote for Trump given his temperament.

During the rally, news broke about an FBI inquiry into Clinton’s emails. Sentiment dramatically shifted as Pence announced the bombshell news from the podium. Days later, Trump won Pennsylvania by 44,292 votes.

Given how eager Republicans appear to challenge the state’s new mail-in election process both before and after Election Day, grabbing votes from every single county is more critical than ever.

Circus monkeys vs. soldiers. Now that’s a show worth sizing up come Nov. 3rd.