Washington( CNN) In the wake of reports that President Donald Trump told former FBI Director James Comey to terminate a probe into former national security consultant Michael Flynn, questions are being raised about whether the President’s acts amounted to blockage of justice.

“‘Close it down’ is an instruction to stop investigating President Trump’s campaign, ” CNN senior legal analyst Jeffrey Toobin told CNN’s Wolf Blitzer Tuesday. “Richard Nixon was impeached in 1974 for telling the FBI to stop an investigation of his campaign. That’s what Watergate was.”

Here’s a look at the exact legal definition of the word — and its potential legal ramifications for a chairman of the United States.

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