Sen. Dianne Feinstein (D-Calif.) speaks to President Trump during a meeting with lawmakers on immigration at the White House on Jan. 9, 2018. (JIM WATSON/AFP/Getty Images)

As the boss of the country’s chief law enforcement official, President Trump has a keen eye for possible violations of the law. Well, that’s not entirely true. Trump has a keen eye for possible violations of the law in the sense that he likes to allege that his political opponents might have broken the law, even in cases where there’s no conceivable way that they have done so.

Consider his tweet on Wednesday about Sen. Dianne Feinstein (D-Calif.), who on Tuesday unilaterally released the testimony of Fusion GPS founder Glenn Simpson.

Possibly illegal! Wow. That must be serious.

This, of course, is the point. I feel confident that Feinstein, who has served as a senator for a quarter-century, would make sure she wasn’t violating the law before taking such an unusual step to share important information (that, not coincidentally, makes Trump look bad). Instead of accusing Feinstein of breaching norms, a critique with more validity but that has an unfortunate rock-in-glass-house effect for Trump, he ups the ante as high as he can go: Did Feinstein … break the law??

The Russia probe got its start with a drunken conversation, an ex-spy, WikiLeaks and a distracted FBI. (Meg Kelly/The Washington Post)

He does this all the time. He’s done it on at least 17 occasions since announcing his candidacy for the Republican nomination.

Was Hillary Clinton’s email server … illegal?

Were Clinton’s emails … illegal?

Was Ted Cruz’s personal disclosure form … illegal?

Did the Republican National Committee, then run by his future chief of staff Reince Priebus, send out a fundraising notice that was … illegal?

Did Cruz raise money … illegally?

Seriously though, were Clinton’s emails … illegal?

Was Barack Obama’s amnesty order … illegal?

Was the State Department defending Clinton … illegally?

Was former Democratic National Committee chair Donna Brazile’s sharing of debate questions with Clinton … illegal?

No, seriously, did she?

Were the 3 million votes cited by a random guy on Twitter cast … illegally?

Did the former attorney general not prosecute Clinton … illegally?

Was former FBI director James Comey sharing an unclassified memo with a friend to give to the press … illegal?

Did the Clinton campaign and Obama administration do a lot of unnamed things that were … illegal?

Did Brazile steal the election from Bernie Sanders … illegally?

Did Clinton get debate questions … illegally — unlike this meeting Donald Trump Jr. had with a Kremlin-linked attorney, which is totally being blown out of proportion?

(Trump has also repeatedly complained about leaks of classified information to the press, which is more of a gray area.)

Trump’s use of “illegal” smacks of a schoolkid who knows only one swear word and deploys it often and with ferocity. It’s the meanest, most serious charge he can level, so he levels it.

During the campaign, the tactic was effective. Pillorying Clinton for illegal activity — activity for which she was either never investigated or never charged, mind you — served to bolster his case that Clinton was hopelessly corrupt. Those allegations led to the “lock her up” mantra and, to some extent, his victory, to the extent that it contributed to skepticism about Clinton’s candidacy.

Against everyone else, Feinstein included, it’s in part an attempt at objectivity. Trump doesn’t like that Feinstein released the transcript, since, among other things, it repeatedly contradicts his own unsubstantiated claims. He sees the charge of “illegal” as not only a pejorative but an outside validator of his frustration. Look, he’s essentially saying, this is about the law, not about me being cranky.

For the most part, it’s actually about him being cranky.