From an analysis by Dan Balz, Washington Post:

The firing of FBI Director James Comey brought to a stunning conclusion one of the most controversial chapters in the bureau’s modern history. Its timing raised fresh and potentially troublesome questions about the future of the investigation Comey was overseeing into possible links between associates of President Donald Trump’s campaign and the Russian government.

There was a certain irony to the explanation offered for the dismissal — it focused on Comey’s handling of the investigation of Hillary Clinton’s emails. Many Democrats, including Clinton, believe that Comey’s reopening of the inquiry late in the campaign contributed to Trump’s victory last November. That’s one reason that, by the time of his dismissal, Comey had few public advocates and many detractors. …

That might explain why Trump’s order to fire him produced, initially at least, somewhat muted reactions among elected officials in both parties, or at least reactions that offered no clear defense of the FBI director.

But as the hours passed and the shock of the announcement rippled more widely, Democrats and some Republicans began to raise concerns about the timing and therefore the possible implications for a president whose administration has been clouded since its start by the Russia investigation, with any number of Democrats accusing Trump of an abuse of power.

Those concerns about what could happen to that probe were summed up most succinctly in a tweet by Robby Mook, Clinton’s campaign manager, who wrote: “Twilight zone. I was as disappointed and frustrated as anyone at how the email investigation was handled. But this terrifies me.”…

Comey’s public statement earlier this spring that the bureau was looking into those allegations made it clear that, whatever the president said or tweeted, there was a serious investigation underway that was threatening to his administration. By dismissing Comey on Tuesday, the president has significantly raised the stakes — for the Justice Department, the FBI and ultimately his administration — to demonstrate that the investigation will continue to its rightful conclusion without interference.