He was due later in the evening in Saint Anselm College to give another talk at the New Hampshire Institute of Politics. It's his second appearance this year in the state that hosts the nation's first presidential primary election.
Flake said the FBI investigation will lead to additional interviews and could reveal new information.
Flake told CBS' "60 Minutes" Sunday that the conservative judge's nomination would be "over" if federal investigators determine he lied.
The drawback to having no Plan B for the nomination is that it leaves the White House (almost) completely at Flake's mercy. That's what you're telling me when you vote for him.
Kavanaugh has emphatically denied Christine Blasey Ford's allegation that he sexually assaulted her at a gathering when they were teens.
The Democrats are doing irreparable harm in the name of their own political agenda and have made victims of Judge Kavanaugh and his family, Ms. Ford and all of us, the American people.
"We're considering it here on the floor", McConnell said. "There was a lot of doubt still", Flake said.
"I had been troubled for awhile". "And some of our colleagues said that 'we'll be back here one week from now".
Before Flake spoke, Kerry was asked about the Kavanaugh hearings.
"Let me make it very clear", McConnell stressed. "I thought it was a bad moment in many different ways", he said.
Just as Republicans on the Judiciary Committee were about to favorably recommend the confirmation of Kavanaugh to the Supreme Court on Friday, Flake had a change of heart.
"You don't let that person disappear to the beach, with their clothes stacked in a vehicle, and hide from process".
"I don't think anybody expected, you know, what happened on Friday to happen".
Flake, who is set to retire from the Senate at the end of 2018, has expressed some interest in running for President in 2020.
Which is why Flake's post-Boston stop was notable: disruptive New Hampshire, to test the presidential waters, even while pretending he's just speaking up for the kind of GOP he wants.
"I don't see that happening in my case".
Earlier in the New Hampshire speech, Flake suggested that rather than consider Democrats and Republicans as two warring factions, they might be better viewed as two organs in the same body.
"There is a big concern among a lot of Republicans, traditional Republicans who believe in limited government, economic freedom, free trade, a strong America, American leadership", said Flake. "I think that the Republicans want to be reminded what it means to be a traditional, decent Republican".