It's time for Jim Comey to be quiet.

That's been the case for a long time now — and yet there the former FBI director was on Wednesday, weighing in on the debate over Mitt Romney's op-ed criticizing President Trump.

Comey isn't exactly wrong in his tweet. Trump's claim to have essentially fired Defense Secretary Jim Mattis was ridiculous. So was his historical revisionism about the Soviet Union's invasion of Afghanistan. But that was all plain to see, so it's not like Comey's commentary really helped anything.

And that's the problem. Comey isn't always wrong. In fact, he often seems to be well-intentioned. But frequently, his efforts aren't at all helpful. Even his laudable desire to get out the vote during midterm elections became the object of mockery.

So why won't he just be quiet? That's what former FBI directors tend to do, after all. They serve out a few years leading America's top crime-fighting agency, then retire to go live out a life of private sector riches, sometimes emerging to head up a commission or join a board as an act of continued public service. Mostly, they keep a low public profile, acquiring a kind of above-the-fray elder statesman status in the process.

Comey was never, ever above the fray.

This has sometimes been to his advantage, and to the country's benefit. Comey first drew widespread public notice during the George W. Bush administration when, as deputy attorney general in 2004, he engaged in a high-stakes standoff with senior officials who were attempting to pressure Attorney General John Ashcroft — then hospitalized with an illness — into signing papers reauthorizing a secret domestic spying program. Comey won that battle — indeed, the reputation he made for himself with the incident may have propelled him into the position of FBI director.

That's where he ultimately earned the ire of Democrats, not just because the agency investigated Hillary Clinton's email use while she was secretary of state, but because he discussed (overblown) developments in the investigation in the waning days of the 2016 campaign — despite long-standing bureau rules against actions that might affect elections — possibly helping Trump win the presidency.

Comey just couldn't keep quiet. And it wasn't helpful.

Trump's gratitude was limited: He ultimately fired Comey. That helped trigger Robert Mueller's appointment as special counsel, which means it is possible that Comey's actions will end up causing both the major 2016 nominees to lose the presidency.

That would be quite an accomplishment.

Maybe you can't blame Comey: His unceremonial dismissal made it a bit more difficult for him to follow the circumspect precedent of other former FBI directors who cashed in and took the elder statesman route. Certainly he deserved the opportunity to defend his honor and professionalism after Trump dumped him.

But Comey didn't stop there. He's become an all-purpose commentator, going on a highly publicized book tour and criticizing Republicans when they speak badly of the FBI, roll over for Trump, or even release a memo.

Aside from not being very helpful, the other problem with all this is that Comey remains a potential witness in a criminal investigation involving the president. Did Trump fire him in order to short-circuit the Russia investigation? That's one item Mueller is investigating. We don't yet have the results of that investigation, though hopefully that day is drawing near. The more Comey opens his mouth with criticisms of Republicans, though, the easier it becomes for Trump and his allies to paint Comey as a biased partisan, somebody with too much of a chip on his shoulder to treat the president fairly. Rudy Giuliani must giggle with glee every time Comey pops up again in the headlines.

Comey has had a long and mostly distinguished career in public service. It's clear he believes he still has something to contribute to American democracy. For now, though, the best service he can perform is to take a vow of public silence.