Still, the question of intent remains. But if it's true that this conversation occurred as reported and as Comey details, it would appear that the president wanted Comey to make a decision regarding the investigation based on something other than the merits of the case -- and that's obstructing justice by any reasonable standard.

The third potential instance of obstruction is Trump's alleged conversation with Director of National Intelligence Dan Coats. According to the Washington Post, Trump asked Coats in March "if he could intervene with then-FBI Director James B. Comey to get the bureau to back off its focus on former national security adviser Michael Flynn in its Russia probe." As with the Comey interactions, the whiff of obstructionism is strong here.

These are all discrete cases, Gurulé says, and they shouldn't be conflated. Even if there's a sound justification for Comey's firing, "that doesn't pertain at all to the conversation between Trump and Comey or between Trump and Coats."

Particularly if the prospect of impeachment is in question, whether Trump committed obstruction of justice is relevant, but that doesn't necessarily make it more or less likely to happen. Ultimately, as Christopher Slobogin, a professor of criminal law at Vanderbilt University, told me, "Congress gets to decide what constitutes a high crime and misdemeanor for impeachment purposes."

Which is to say, even if Trump did obstruct justice, he will not be impeached unless a Republican-controlled Congress decides he ought to be.