At an event late last week, Donald Trump declared with confidence, “You’re not going to teach a criminal not to be a criminal,” as if the maxim were just common sense. A day later, the former president echoed the line at an unrelated event.

“A criminal is a criminal,” he said. “They generally stay a criminal and we do not have time to figure it out.”

In context, Trump appeared to be referring to migrants hoping to enter the United States, but there was a degree of irony hanging overhead. In a little more than a year, a jury found Trump guilty of 34 felonies in his hush money case, a different jury held him liable for sexual abuse, and a court found that Trump oversaw a business that engaged in systemic fraud.

A little self-awareness goes a long way, and by any reasonable measure, “You’re not going to teach a criminal not to be a criminal” is a phrase the GOP nominee probably ought to avoid.

It was against this backdrop that Vice President Kamala Harris’ campaign made its first big ad buy of the cycle, investing $50 million in support of a spot called “Fearless.”

The minute-long commercial is worth watching in its entirety, but of particular interest was the opening message in the spot.

“As a prosecutor, she put murderers and abusers behind bars,” the narrator tells viewers. “As California’s attorney general, she went after the big banks and won $20 billion for homeowners.”

The ad goes on from there, but from the outset, the message was unambiguous: Team Harris wants voters to know about her background in law enforcement, and her role in locking up criminals.

A day earlier, the incumbent vice president’s political operation sent a news release to reporters on crime, noting not only the significant improvement in crime rates during the Democratic administration, but also saying plainly: “Our opponent Donald Trump is a criminal.”

A campaign spokesperson added, “On crime and the border: Donald Trump’s lies are not facts and Donald Trump’s angry rants are not results. Under Trump, America saw unprecedented violence, ineptitude, and division. Right now, America is stronger and safer because of the work of the Biden-Harris administration: Violent crime is at record lows, the border is more secure, and unlike Donald Trump, the vice president is committed to enforcing the law, not breaking it.”

The former president talks about crime as if it’s a campaign issue on which he has an advantage, despite his felonious past. It appears his assumptions are being tested.

At a campaign rally last week, Trump told an audience that the Democratic campaign was telling the electorate, “‘I’m the prosecutor, and he is the convicted felon.’” He added, “I don’t think people are going to buy it.”

The trouble, of course, is that the message has the benefit of being true. As for whether voters will buy it or not, we’ll find out in about 98 days.