While President Trump and FBI Director Christopher Wray aren’t happy with one another, Trump’s appointment of Wray has never been more personally valuable to the president.

Why? By showing independence from the White House and resisting Trump's pressure on the FBI, Wray is confirming that Trump made a good and prudent decision in appointing him as director.

This isn't merely a political boon, or a pleasant appearance. It has potential importance legally, because it can inform special counsel Robert Mueller’s consideration of obstruction of justice charges, which circle around the president's firing of former FBI Director James Comey.

Now don’t get me wrong, I’ve always thought the case for obstruction charges was weak. That is unless Mueller has multiple sources or varied, credible evidence testifying to Trump’s desire to prevent the process of law.

Nevertheless, the central pivot on which any obstruction charge will pass or fail is a jury’s interpretation of why Trump fired Comey. What was he trying to accomplish?

The president says he did so under the advice of Deputy Attorney General Rod Rosenstein. Trump’s detractors say that he did so because Comey failed to pledge his personal loyalty to Trump and refused to save Trump’s short-lived national security adviser Michael Flynn from prosecution.

But, here’s the thing.

Now that the individual the president chose to replace Comey is showing such independence from Trump, any Trump courtroom lawyer will have a pretty compelling line of defense for the president.

Namely, he or she could tell a jury, “if my client was so determined to obstruct justice, what possible rationale did he have for firing Comey then appointing someone who was so committed to that which the prosecution says Comey was originally fired for: the objective pursuit of justice? Surely if the prosecution’s case is true,” the lawyer might say, “the president would have picked a more malleable character and relied on the Republican Senate majority to push that confirmation through? He did not because this was never about obstruction.”

Again, the operative fact here is that Wray was well-regarded as an objective public servant during his confirmation hearings and is even more so regarded now.

Where some might say that Trump specifically chose Wray to deflect criticisms that he was trying to obstruct justice, those claims would render hollow in a criminal court of law. After all, in criminal court, the prosecution must prove not that a defense has holes in it, but that its own accusation is beyond all reasonable doubt true.

Trump’s choice of Wray and Wray’s reflective conduct since that choice gives the president a useful weapon of defense. It gives Trump’s defense team more credibility to tell the jury that which Trump has insisted was the case: that he fired Comey on the prudent advice of Rosenstein and acted justifiably as head of the executive branch.