Republican presidential candidate, Ohio Gov. John Kasich, speaks at a rally in Traverse City, Mich., March 5, 2016 (John L. Russell/AP)

Ohio Gov. John Kasich (R), who is considering a Republican primary challenge against President Trump in 2020, said he was unsettled by the president’s news conference on Monday, where Trump refused to support the conclusion of U.S. intelligence agencies that Russia interfered in the 2016 presidential election.

“It’s depressing, really unlike anything we’ve seen in my lifetime,” Kasich said in a phone interview with The Washington Post. “A president of the United States saying, ‘You know, I kind of believe a former KGB agent over our intelligence community.’”

Kasich added, “This is a sad day.”

But Kasich acknowledged that his dismay may not be shared by most Republicans. He said he would be closely watching fellow GOP officials in the coming days to see if the party rallies around Trump.

“I’m wondering what the congressional impact will be, what the reaction of his base will be,” Kasich said. “It has seemed that regardless of what he says, they stay with him. We will have to wait and see.”

Anyone mulling a 2020 bid “would have to see what ultimately the reaction of the Republican Party is” before concluding that Monday’s news conference represented a turning point, Kasich said.

Kasich said Cabinet members and administration leaders would have to make their own decisions about whether to keep working with Trump.

“That’s their decision,” he said.

Kasich, who has been increasingly critical of Trump’s foreign policy in recent weeks, said he would continue to speak out. Thursday, he spoke at the National Press Club in Washington and called Trump’s approach “wrecking ball” diplomacy.

Kasich competed unsuccessfully against Trump for the GOP nomination in 2016. He placed second in the New Hampshire primary, finishing behind Trump.

Earlier this month, Kasich announced that he would heading back to New Hampshire in the fall for a speech at the Nackey S. Loeb School of Communications in Manchester.

Sen. Jeff Flake (R-Ariz.), another Trump critic considering a 2020 run, called Trump’s comments at the news conference on Monday “shameful.”