At a fiery rally in Erie, Pennsylvania on Wednesday night, President Trump unloaded a series of broadsides on two-term Sen. Bob Casey, characterizing him as a pale shadow of his late father who values illegal immigrants more than U.S. citizens.

Trump also reiterated his commitment to the state's coal industry and promised immediate support to Floridians impacted by Hurricane Michael.

Trump opened the rally by saying that "all of Pennsylvania, and all of America sends its unwavering love and support" to those in the path of the hurricane. Offering his "thoughts and prayers," he vowed that "we will spare no expense" to address the storm, and that he'd traveling to Florida "very, very shortly."

"We are unleashing the power ... of clean, beautiful Pennsylvania coal," Trump said to applause, after touting the economic growth under his administration. "We are putting our miners back to work. We are putting our steelworkers back to work."

Trump has made several visits to Pennsylvania since becoming the first Republican presidential candidate to carry the far-left state since George H.W. Bush in 1988. He was stumping for Republican Reps. Mike Kelly, Glenn "GT" Thompson, and Lou Barletta, among others, as well as gubernatorial candidate Scott Wagner.

"The best thing I can say about Scott Wagner is he has the endorsement of Judge Jeanine," Trump said, referring to Fox News host Jeanine Pirro. He acknowledged that Wagner, who is far behind in the polls, is up against a "tough" opponent.

Kelly is facing a challenge from Democrat Ron DiNicola, while Barletta is mounting an uphill campaign to unseat two-term Democratic Sen. Bob Casey.

"While Lou is fighting for you, Bob Casey is fighting to protect violent criminal aliens," Trump said Wednesday, to loud boos. "Bob Casey voted in favor of deadly sanctuary cities that release thousands upon thousands of illegal alien criminals and vicious gang members to prey on Pennsylvania's streets. No good."

"Bob Casey even voted against Kate's Law, named for Kate Steinle, who was gunned down by a five-time-deported illegal alien who should never have been in our country," Trump said. The legislation, which is stalled in the Senate, would hike the penalties for illegal immigrants who attempt to re-enter the country. Casey has opposed it, saying the best solution is to focus on securing the border.

"Bob Casey puts criminal aliens ahead of U.S. citizens. Always has. ... He's banking on the name of his father," Trump said. Casey's father, who died in 2000, previously served as the state's governor from 1987 to 1995.

Trump has long attacked Casey. At a rally in Pennsylvania in August, Trump mocked Casey as "Sleepin' Bob" and said the longtime Democratic senator was a truant who is "so overrated."

"He's banking on the name of his father." — President Trump on Sen. Bob Casey, D-Pa.

"I'm not sure I ever met Bob Casey," Trump said. "Now, his father was a good man. Knew him a little bit. But we're dealing with a totally different person. I don't know this man."

"He's not an obstructionist, he's worse: He will do whatever Schumer, Pelosi, and the new star of the Democrat Party tells him to do," Trump said, referring to Rep. Maxine Waters, D-Calif. "Very low IQ," Trump added.

WATCH: ERIC HOLDER URGES DEMOCRATS TO FIGHT BACK AGAINST REPUBLICANS: 'WHEN THEY GO LOW, KICK 'EM'

Staring down tough midterm elections, the president and top Republicans have sought to characterize mob tactics as a hallmark of modern progressivism, in the wake of comments by Waters encouraging protesters to confront and "push back on" White House officials in public places. Trump has often mockingly called Waters a "leader" of the Democratic Party, even as he said her IQ hovers in the mid-60s.

In recent weeks, liberal fury over the nomination and eventual confirmation of Associate Supreme Court Justice Brett Kavanaugh reached a tipping point, with groups of demonstrators shouting at senators on Capitol Hill and even attempting to claw their way inside the Supreme Court building. Protesters also chased Sen. Ted Cruz, R-Texas, and his wife out of a restaurant, and activists have sent death threats to Kavanaugh and top Republicans.

Trump on Wednesday night called Democrats' behavior a "disgrace" and said he "never even thought" about abandoning Kavanaugh in the face of several uncorroborated sexual misconduct allegations. He also took a shot at the so-called #MeToo movement that opposed Kavanaugh, implying that its proponents are so politically correct that they would insist on the gender-neutral phrase "the person that got away."

RADICAL PROTESTERS CHASE TED CRUZ, WIFE OUT OF RESTAURANT, CHANTING 'BELIEVE ALL WOMEN'

Trump also published an op-ed in USA Today that attacked Democrats over "Medicare for All" health care proposals. In his op-ed, Trump said Democrats have moved away from centrism, claiming the "new Democrats are radical socialists who want to model America's economy after Venezuela."

Before he flew to Erie, Trump said he faced a lose-lose "quagmire" because of the timing of the hurricane. Last month, the White House canceled rallies in Mississippi and Missouri because of Hurricane Florence, which hit the Carolinas.

The president's rallies have increasingly given him a platform to test-fire new attacks against high-profile Democratic rivals, as well as to introduce new policies.

At a rally Tuesday night in Iowa, Trump announced that he would remove a federal ban on summer sales of gasoline with high-ethanol blends, permitting year-round sales of gasoline with 15 percent ethanol or E15.

FOX NEWS POLLS SHOW KAVANAUGH SLUGFEST BOOSTING GOP IN KEY SENATE RACES

"We’re going with E15 year-round. I made that promise to you during the campaign. I made that promise to you during the primaries," he said. "Promises made, promises kept."

The long-expected announcement is something of a reward to Iowa Sen. Chuck Grassley, who as Senate Judiciary Committee chairman led a contentious but successful fight to confirm Kavanaugh to the Supreme Court. The veteran Republican lawmaker is the Senate's leading ethanol proponent and sharply criticized the Trump administration's proposed rollback in ethanol volumes earlier this year.

At the rally Wednesday, Trump again mocked Sen. Dianne Feinstein, D-Calif., for her denial last week that she had anything to do with the leak of Christine Blasey Ford's letter accusing Kavanaugh of sexual assault.

Ford, who sent the letter to Feinstein's office in July, publicly revealed herself just days before a planned Judiciary Committee vote on Kavanaugh's confirmation when news of her letter leaked to The Intercept. Senate Republicans have strongly implied that, because no Republicans had access to the letter, Feinstein or a member of her staff was involved in the leak.

JUDICIARY CMTE CHAIRMAN CONDEMNS FEINSTEIN'S HANDLING OF FORD LETTER: 'I CANNOT OVERSTATE HOW DISAPPOINTED I AM'

As Trump imitated Feinstein's denial in Iowa on Tuesday, the crowd chanted, "Lock her up," a phrase that Trump supporters previously applied almost exclusively to former presidential candidate Hillary Clinton.

For her part, Feinstein, the ranking member of the Judiciary Committee, suggested that one of Ford's friends had leaked information about the letter. She also, in no uncertain terms, condemned Trump's rhetoric.

"Dr. Blasey Ford knows I kept her confidence, she and her lawyers said so repeatedly," Feinstein said Wednesday. "Republican senators admit it. Even the reporter who broke the story said it wasn't me or my staff. The president's remarks are ridiculous and an embarrassment."

Trump is scheduled to attend another rally Friday evening in Ohio and on Saturday evening in Kentucky.

Fox News' Brooke Singman and The Associated Press contributed to this report.