Story highlights Ken Starr explained there is an extraordinarily high bar for proving obstruction of justice

Starr's investigation of President Bill Clinton led to his impeachment in 1998

(CNN) Ken Starr, the independent prosecutor who spent years investigating President Bill Clinton's White House, said Thursday there is no viable case for obstruction of justice charges against President Donald Trump based on the evidence publicly available so far.

"It's too soon too tell," Starr told CNN's Alisyn Camerota on "New Day." "From what I have seen, no."

"We don't know a whole lot, but the the answer is no," he added.

Starr, whose own investigation lead to the impeachment of Clinton in 1998, explained there is an extraordinarily high bar for proving obstruction of justice. He added that even if former FBI Director James Comey's description of an encounter , in which, Trump allegedly said he hoped he would drop a probe into then-national security adviser Michael Flynn was true, it would likely not rise to the level of a crime.

"Obstruction of justice is really a hard crime to make out," Starr said. "Comey said in his testimony that even though the expression (from Trump) was 'hope,' he took it as a directive, but what we know is he (Trump) didn't do anything about it. He did not dismiss the investigation or curtail the investigation."

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