Flake, a Republican from Arizona, left the door open for himself, though he said he thinks it's unlikely. "I think the odds that it will be me are long, but I am not ruling it out".
"There is nothing that will be more vital to expunge from the American record than this frenzied attack on the truth", said Flake, adding what will be remembered of Trump is his war on objective reality and his reflexive impulse to speak falsely - a character trait that Flake contended is absolutely devastating for an American President.
A full year before presidential candidates typically begin courting local voters, there is already an expectation among top Republicans that Trump will face a challenge from within his own party in the next presidential contest.
Flake, who is not running for re-election this year, said Thursday that he does not now plan to challenge Trump in 2020, but also would not rule it out.
Flake will deliver a speech Friday morning titled "Country Over Party", as part of the esteemed "Politics and Eggs" speaker series at Saint Anselm College. Flake cited people in his party who appeared to admire what he said were the "strategic underpinnings of the daily chaos in the White House".
The visit marked the first time Flake has been to New Hampshire - home to the first-in-the-nation presidential primary - since campaigning there with Arizona Senator John McCain in 2008.
Despite Flake's claim that he is not planning a challenge to Trump, analysts said his trip to New Hampshire raises eyebrows.
Flake acknowledged that Trump is now too popular with the Republican base to lose a primary in 2020.
"President Trump obviously would never win the election, general election in NY, but he's our president". Rose put Flake's chances of beating Trump after two years out of office at "less than zero". He announced his decision to not run for re-election last fall.
"In the wake of this storm, we will once again make clear to our allies that we are allies and we will never again be afraid to remind friend and foe alike that it is our values that make America, America", he said.