What did Donald Trump do today?

He asked a rhetorical question about convicted criminal Joe Arpaio.

At a campaign rally tonight in Phoenix, Trump asked the crowd "Was Sheriff Joe convicted for doing his job?" The reference was to former Maricopa County Joe Arpaio, a political ally of Trump's who was implicated in literally dozens of criminal or unethical acts before being voted out of office.

In fact, Joe Arpaio was convicted of federal criminal contempt because he refused to do his job. Arpaio ordered his deputies to racially profile Latinos and detain people they believed to be in the country without documentation, even if they were not suspected of having committed a crime. After repeatedly ignoring orders from a federal judge to stop, Arpaio was found guilty of criminal contempt for having "willfully violated the order by failing to do anything to ensure his subordinates' compliance and by directing them to continue to detain persons for whom no criminal charges could be filed." In the case that gave rise to the orders, Arpaio destroyed evidence and on separate occasions opened investigations into both the presiding judge and the judge's wife.

Trump, who has recently become very interested in pardons, all but promised the crowd he would pardon Arpaio at a later date, saying, "You know what, I'll make a prediction: I think he's going to be just fine, OK? But I won't do it tonight, because I don't want to cause any controversy. But Sheriff Joe should feel good."

So what?

• It is not possible for a law-abiding police officer to be convicted of a crime for "doing his job," and no president should suggest otherwise.

• It's disgraceful for a president to use the power of the pardon to try to boost his popularity.