Not since Watergate has a president dismissed the person leading an investigation bearing on him, and Mr. Trump’s decision late Tuesday afternoon drew instant comparisons to the “Saturday Night Massacre,” when President Richard M. Nixon ordered the firing of Archibald Cox, the special prosecutor looking into the so-called third-rate burglary that would eventually bring Nixon down.
In his letter informing Mr. Comey that he was terminated as F.B.I. director, Mr. Trump made a point of noting that Mr. Comey had three times told the president that he was not under investigation. But Mr. Comey has said publicly that the bureau is investigating Russia’s meddling in last year’s presidential election and whether any associates of Mr. Trump’s campaign were coordinating with Moscow.
While Mr. Trump said he acted on the recommendation of Attorney General Jeff Sessions, he had left little doubt about his personal feelings toward Mr. Comey or the Russia investigation in recent days. “Comey was the best thing that ever happened to Hillary Clinton in that he gave her a free pass for many bad deeds!” he wrote on Twitter a week ago.
“The Russia-Trump collusion story is a total hoax, when will this taxpayer funded charade end?” he said Monday.
Some Democrats immediately raised the specter of Watergate and called for a special counsel to lead an independent investigation into the Russian meddling and any links to Mr. Trump’s campaign. “This is Nixonian,” Senator Bob Casey, Democrat of Pennsylvania, said in a statement.
“Not since Watergate have our legal systems been so threatened and our faith in the independence and integrity of those systems so shaken,” added Senator Richard Blumenthal, Democrat of Connecticut.
The paradox, of course, is that Mr. Comey had few fans among Democrats, especially Hillary Clinton, who last week blamed him for steering the election to Mr. Trump by publicly announcing shortly before the election that he was reopening his investigation into her emails.