From the May 21 edition of CNN's Fareed Zakaria GPS:
FAREED ZAKARIA (HOST): There is some argument that there was, Ron, an obstruction of justice when Trump seems to have told Comey to “ease up” on the Flynn investigation.
RONALD KESSLER: No, that's not obstruction. Obstruction is actually impeding the investigation, by covering up, by phony evidence, which happened during Watergate. Nixon actually got the FBI to stop the investigation based on some phony story that he made up about the CIA.
In addition, there's no violation of law if, in fact, the campaign colluded with Russia, whatever that means. The only violation would be an individual who didn't register as a foreign agent, such as Michael Flynn, perhaps.
And finally, this Washington Post story claiming that an aide close to Trump is a person of interest is a total hoax because the FBI doesn't use that terminology whatsoever in any investigation except for violent crime and kidnapping. In a counter intelligence investigation or any other -- most of the other investigations, they never use that term. So, someone made up this story, gave it to a Post reporter. At the Post, they apparently don't know enough about the FBI to recognize that there's no such term in the FBI lexicon.