Here's why Comey couldn't just quit in February

Rep. Peter King, among others, have raised the question of how former FBI Director James Comey could have ethically kept quiet if, as reportedly alleged in one of his memos, President Donald Trump took him aside in February and asked him to end the investigation into Michael Flynn.

Didn't Comey have an obligation at the time to go public with his concerns that the president was obstructing justice, even an obligation to resign in protest?

Well, consider what would have happened if he had done so. Indeed, consider a defense we are hearing Wednesday of the president's comments from February.

Of course, today the retort is obvious: If Trump wasn't making a serious effort to obstruct justice, if he was just engaged in "Oval Office talk" or whatever, then why the hell did this end with him firing the FBI director?

But if Comey had gone public in February, the defense from Republicans would have been that Trump just talks like that, and he wasn't trying to obstruct justice, and you shouldn't take him so literally.

And without Trump having taken a concrete step to obstruct justice, such as firing the FBI director, that defense would have worked.

And if Comey had resigned - or had given the president political license to fire him by breaking publicly with him on a high-profile matter - then Trump would have been able to replace him with a loyal supporter who could have sought to kill the Flynn probe more quietly.

If you work for a private firm, and your boss asks you to do something unethical, you are likely to have an ethical obligation to quit. But Comey worked for the American people, and he seems to have understood that his ethical obligation was to stay in place, refuse the unethical request, and keep a paper trail.