Trump's planned rally at Eastern Kentucky University in Richmond has sparked opposition at the school.
The president has scheduled another rally Saturday night in Kentucky.
Trump also led for a rousing cheer for the state's senior senator, Majority Leader Mitch McConnell.
"We stuck with him all the way because we knew the facts", Trump said, speaking of himself and McConnell, Kentucky's senior USA senator. Others toted placards with slogans including "Believe Women", "Impeach Kavanaugh" and "Listen to Women", reflecting how the tight race is after Kavanaugh's confirmation following accusations of sexual misconduct.
"What the insane, radical Democrats did to Justice Kavanaugh is a national disgrace", Trump said. "I need you to get your friends, get your family, get your neighbors, get your co-workers and get out and vote for Andy Barr", Trump said. "They were on a mission to obstruct, resist, delay, demolish and destroy".
"The Democrats have become totally consumed by their chilling lust for power", he said.
Before leaving the White House for the Richmond rally, Trump met with Pastor Andrew Brunson, who was just released after nearly two years of detention in Turkey.
Brunson was released from house arrest in Turkey on Friday after being imprisoned since October 2016 over alleged ties to an outlawed group.
Trump said Brunson was now back in the USA with his family and thanked Erdogan, adding that the two countries will likely "establish a terrific relationship". "Republicans stand proudly with the heroes of ICE and border patrol and law enforcement".
McConnell said he would continue helping to confirm Trump's judicial appointments and predicted the wave of new judges will "change the court system forever".
"We have ended the war on clean, attractive coal", he said.
Ahead of the rally, Trump backed Barr on Twitter, calling him a "fantastic guy". "Strong on Crime, Tax Cuts, Military, Vets & 2nd A. His opponent will NEVER vote for us, only for Pelosi". "We're putting our miners back to work like never before". Andy has my Strongest Endorsement!
Democrats are focusing on the seat in their drive to regain control of the House. Former Vice President Joe Biden campaigned for McGrath on Friday night.
"This election is bigger than politics", he said.