Two high-profile political events of the last week provided an unintended present from Donald Trump to his rival for the presidential nomination, Hillary Clinton. First in their final debate Wednesday in Las Vegas, and then the next night at the Al Smith charity dinner in New York, Mr. Trump's behavior gave Ms. Clinton venues in which she displayed her superior political skills, knowledge and temperament.
In the debate, she repeated her ability to goad Mr. Trump into excesses of personal invective, misstatements of fact and insensitivity to women. Then, at the officially Democratic but traditionally nonpartisan dinner, she largely maintained a sense of decorum fitting the occasion, as he occasionally overstepped the affair's tradition of good-natured ribbing, drawing audible boos from the invited guests.
In both settings, the Democratic nominee offered a much greater level of comfort and control of the facts expected of a would-be president. In contrast, her Republican opponent in that final debate had gravely wounded himself with his unwillingness to say he would accept the American voters' decision in the election outcome.
In the process, Ms. Clinton offered a convincing challenge to Mr. Trump's strongest argument for claiming the presidency — i.e., that she is totally unacceptable.
The most diehard Trump voters, obviously, will not be swayed. But among the undecided and uncommitted, Ms. Clinton presented herself as more prepared, both in substance and temperament, than the undisciplined and often ill-informed celebrity television star and real-estate tycoon.
Some analysts have argued that had some other Republican secured the nomination — such as Sen. Mario Rubio of Florida, who was defeated and humiliated by Mr. Trump in the GOP primaries, or House Speaker Paul Ryan — he could have handily defeated Hillary Clinton. But Mr. Trump's easy sweep through the primaries only demonstrated the dearth of political talent in the decimated Grand Old Party.
In the first segment of the third debate, Mr. Trump showed a much more restrained and issue-focused version of himself, suggesting greater preparation than before. Ms. Clinton's earlier chiding that she had not only prepared for the next debate but also to be president was a telling dig at Mr. Trump's dismissive attitude.
Ms. Clinton, as the first woman nominee for the highest office, was particularly effective playing on Mr. Trump's disparagement of females, observing that he "thinks belittling women makes him bigger" and that he "goes after their dignity, their self-worth. ... That's who Donald is."
His response was to pivot to his contention that the election was "rigged" against him, which led to his colossal political gaffe of declining to commit himself to the election result. Chief aides scurried to back away, Republican National Chairman Reince Priebus arguing that all Mr. Trump was saying was that he was he was "not going to forego" his right to a recount in a close election. But Ms. Clinton renounced Mr. Trump's observation as a "horrifying" rap at a pillar of American democracy.
At the charity dinner, Mr. Trump got a laugh in saying that Ms. Clinton in bumping into him said, "Pardon me." To which he replied, he said, "Let me talk to you about that after I get into office." But Mr. Trump also repeated that she was "so corrupt" and pretended "not to hate Catholics" — a particularly low blow as much as she was sitting next to Cardinal Timothy M. Dolan of New York.
Ms. Clinton in her turn engaged in self-deprecation, saying, "I took a break from my rigorous nap schedule to be here." But then she ribbed Mr. Trump on his evaluating women's appearance, saying "He looks at the Statue of Liberty and sees a '4,' maybe a '5' if she loses the torch and tablet and changes her hair."
In all, the two nights' outings appeared to do nothing to slow Mr. Trump's slippage in the polls, while again showcasing Ms. Clinton's greater ease in the different political settings. On following Mr. Trump to the microphone at the dinner, she quipped: "It's amazing I'm up here after Donald. I didn't think he'd be OK with a peaceful transition of power." Mr. Trump sat on the other side of the cardinal, a slight grin on his face, as she got in a joking reference to what is turning out to be no joke for him.
Jules Witcover is a syndicated columnist and former long-time writer for The Baltimore Sun. His latest book is "The American Vice Presidency: From Irrelevance to Power" (Smithsonian Books). His email is email@example.com.