WILKES-BARRE: Republican Donald Trump said on Saturday he believed Democrat Kamala Harris will be easier to beat than President Joe Biden even as some polls showed her edging ahead in the race for the Nov. 5 presidential election.

Trump, the former president, held a rally on Saturday in Wilkes-Barre in the northeastern part of Pennsylvania, a state looming large in the campaign. Vice President Harris will conduct a bus tour of western Pennsylvania starting in Pittsburgh on Sunday, ahead of the kickoff of the Democratic National Convention on Monday in Chicago.

"I believe she will be easier to beat than him," said Trump, referring to her as "radical" and a "lunatic."

Pennsylvania was one of three Rust Belt states, along with Wisconsin and Michigan, that helped power Trump's upset victory in the 2016 election. President Joe Biden, who grew up in Scranton, Pennsylvania, flipped the trio back to the Democrats in 2020.

The three states are true bellwethers - the only U.S. states to have voted for the eventual winner of the presidential race in every cycle since 2008.

With 19 electoral votes out of the 270 needed to secure the White House, compared with 15 in Michigan and 10 in Wisconsin, Pennsylvania may be the biggest prize in this year's election.

A statistical model created by Nate Silver, an election forecaster, estimates that Pennsylvania is more than twice as likely as any other to be the "tipping point" state - the one whose electoral votes push either Harris or Trump over the top.

Harris' entry into the race after Biden ended his reelection bid last month has upended the contest, erasing the lead Trump built during the final weeks of Biden's shaky campaign. Harris is leading Trump by more than two percentage points in Pennsylvania, according to the poll tracking website FiveThirtyEight.

Blanketing airwaves with ads 

Trump won Pennsylvania in 2016 by about 44,000 votes, a margin of less than one percentage point, while Biden prevailed by just over 80,000 votes in 2020, a 1.2% margin.

Both campaigns have made the state a top priority, blanketing the airwaves with advertisements. Of the more than $110 million spent on advertising in seven battleground states since Biden dropped out in late July, roughly $42 million was spent in Pennsylvania, more than twice any other state, the Wall Street Journal reported on Friday, citing data from the tracking site AdImpact.

Democratic and Republican groups have already reserved $114 million in ad time in Pennsylvania from late August through the election, more than twice as much as the $55 million reserved in Arizona, the next highest total, according to AdImpact.

The Harris campaign said on Saturday it planned to spend at least $370 million on digital and television ads nationwide between the Labor Day holiday on Sept. 2 and Election Day.

The battleground states - seen as critical for winning the election - also include Arizona, North Carolina, Nevada and Georgia.

New polls published on Saturday by the New York Times found Harris leading Trump among likely voters in Arizona, 50% to 45%, and in North Carolina, 49% to 47%, and narrowing the former president's leads in Nevada, 47% to 49%, and in Georgia, 46% to 50%. A pollster from the Trump campaign said the poll results underestimated the Republican candidate's support.

Trump and Harris have visited Pennsylvania more than half a dozen times each this year. Trump was wounded during an assassination attempt at his rally near Butler, Pennsylvania, on July 13.

He has said he will return to Butler in October, and also announced he will give remarks on the economy at a campaign event in York, Pennsylvania, on Monday. Trump's running mate, U.S. Senator JD Vance, will deliver remarks in Philadelphia that day as well.

Trump's trip on Saturday to Wilkes-Barre in Luzerne County is aimed at solidifying support among the white, non-college-educated voters who lifted him to victory in 2016. The blue-collar county voted Democratic for decades before swinging heavily toward Trump in 2016, mirroring other similar regions around the country.

Trump won Luzerne in 2020 by 14.4 percentage points, a smaller margin than his 19.4 point win in 2016. With Biden out of the picture, Trump likely sees room for gains in this area of the state, said Chris Borick, a political science professor at Muhlenberg College.

"This is the type of place where Trump has lots of strengths," Borick said, referring to the state's northeast region. "Marginal gains in a region like this certainly could have some impact on his ability to take back Pennsylvania."

Harris and her running mate, Minnesota Governor Tim Walz, will make multiple stops across Allegheny and Beaver counties on Sunday, the campaign said. The tour is the first time Harris, Walz and their spouses have campaigned together since their first rally as a presidential ticket in Philadelphia earlier this month.

Pennsylvania was at the heart of Biden's victorious 2020 strategy across the Rust Belt states: limiting Trump's margins among working-class white voters while building majorities among suburban voters and driving higher turnout in urban areas with large Black populations.

The Harris campaign is pursuing a similar "win big, lose small" strategy, aiming for large margins in the cities and suburbs of Philadelphia and Pittsburgh, while limiting losses in smaller counties like Beaver County, where Trump won 58% of the vote in 2020.