This one by a lawyer who should know better.
James Robenalt, a partner at Thompson Hine law firm who wrote a book about the Watergate scandal, said Trump may have complicated things for himself with this statement. The president is now facing an investigation into whether he obstructed justice with his firing of Comey.
"He's trying to influence a witness," Robenalt said. "There are multiple obstruction crimes under our law, and one of them is intimidating a witness."
https://www.yahoo.com/finance/news/legal-expert-explains-trump-could-142300654.html
This is what the law says:
18 U.S. Code § 1512 - Tampering with a witness, victim, or an informant
(e) In a prosecution for an offense under this section, it is an affirmative defense, as to which the defendant has the burden of proof by a preponderance of the evidence, that the conduct consisted solely of lawful conduct and that the defendant’s sole intention was to encourage, induce, or cause the other person to testify truthfully.