WASHINGTON — US Vice President Kamala Harris brings her presidential campaign to the critical state of Pennsylvania on Sunday before heading on to Chicago, where the Democratic Party this week is due to nominate her to take on Donald Trump in the Nov. 5 election.

Opinion polls have shown Harris bringing fresh energy to the campaign and closing the gap with former President Trump both nationally and in many of the eight highly competitive states including Pennsylvania that will play a decisive role in picking Democratic President Joe Biden's successor.

"I’ve been to every convention since I was able to vote, and I can say I’ve not felt this kind of energy and electricity at any convention other than the one for Barack Obama," said Democratic Illinois Governor J.B. Pritzker on CNN's State of the Union on Sunday.

Obama in 2008 was elected as the historic first Black president of the United States. Harris, who is Black and has Asian heritage, would be the first woman president if she wins in November.

Harris and her running mate, Minnesota Governor Tim Walz, plan a bus tour beginning in Pittsburgh that will make several stops during the day through Allegheny and Beaver counties, areas that her campaign considers critical to winning Pennsylvania.

The trip comes the day after a Trump speech in northeast Pennsylvania where he derided Harris as a "radical" and a "lunatic," saying he believed she would be easier to beat than Biden, 81, who under pressure from his own party after a disastrous debate against Trump.

Pennsylvania was one of three Rust Belt states, along with Wisconsin and Michigan, that helped power Republican Trump's upset victory in the 2016 election.

Biden, who grew up in Scranton, Pennsylvania, flipped the trio back to the Democrats in 2020, and Harris aims to hold on to them.

After her Pennsylvania appearances, Harris will go on to Chicago for the kick-off of the Democratic National Convention on Monday.

Sources said on Saturday that she is likely to join Biden on stage at the convention on Monday as he passes the torch to her as the party's nominee for president.

The Trump campaign will try to counter-program the convention with a series of swing-state events this week. He will visit a manufacturing facility in York, Pennsylvania, on Monday, where his campaign says he will focus on the economy, and a county sheriff's office in Howell, Michigan, on Tuesday to talk about safety and crime.

Trump and his running mate Senator JD Vance will travel to Asheboro, North Carolina, on Wednesday for remarks on national security, and on Friday Trump will join Turning Point Action, a group founded by conservative activist Charlie Kirk, for a rally in Glendale, Arizona, aimed in part at highlighting efforts to boost turnout.

Trump supporters said they hope he will refocus his campaign on policy rather than the repeated personal attacks against Harris he has leaned heavily on in the weeks since she emerged as the Democratic candidate.

"President Trump can win this election. His policies are good for America and if you have a policy debate he wins. Donald Trump the provocateur, the showman, may not win this election," Republican US Senator Lindsey Graham said on NBC's "Meet the Press" on Sunday. "Policy is the key to the White House." — Reuters