"Well, you know, sometimes he says things I don't agree with and I think they don't resemble the facts", Kasich replied, to laughter, but he said using terms like "liar" is not helpful for America.
In the official statement sent to Bustle, Sanders calls for four things he believes we need "now more than ever" - a special prosecutor for the Russian Federation investigation, public recordings from the Oval Office, an independent FBI director, and Republicans holding Trump accountable.
Both Sanders and Kasich ran unsuccessful campaigns for president.
Gov. John Kasich said House Speaker Paul Ryan should be more aggressive in speaking out against President Donald Trump in the wake of news that Trump asked former FBI Director James Comey to end an investigation into former national security adviser Michael Flynn.
"I hope you can see your way clear to letting this go, to letting Flynn go", Trump told Comey, according to the memo.
Kasich agreed: "We find ourselves in a serious situation today".More news: This Week's WWE Smackdown Live Viewership Hits Record Low Heading Into Backlash
"It is clear that whomever President Trump handpicks to lead the FBI will not be able to objectively carry out the Russian Federation investigation", he said.
"I don't like people who say, 'I told you so, ' but". "President you have to resign.' But we're a long way away from anything like that".
"I think John is thinking about becoming a democratic socialist", Sanders quipped in a reference to his own political identification. "But it is absolutely imperative that Republicans come forward".
"President Trump, in a reckless and unsafe manner, has revealed highly classified information to the Russians at a meeting in the Oval Office, information that could expose extremely important sources and methods of intelligence gathering in the fight against ISIS", Sanders said in the statement.
The first question at CNN's town hall asked if Kasich and Sanders believed there was "sufficient grounds for impeachment" and if either politician would support such an effort.