Kareem Abdul-Jabbar, the NBA's all-time leading scorer, is a former cultural ambassador for the United States and the author of several bestselling books. His latest novel is "Mycroft Holmes."

Trump is withering in response to questions he doesn’t like. (Mark Humphrey/AP)

Ernest Hemingway once said that courage was “grace under pressure.” Two presidential candidates, Donald Trump and Bernie Sanders, have recently tested this proposition. And how each man responded revealed the type of person he is and the type of president he would make: Trump authored his own doom, and Sanders opened immense new possibilities as a compassionate person and serious candidate for president.

Here’s where it went fatally wrong for Trump. During the GOP debate on Fox, when Megyn Kelly famously queried him about his attitude toward women (whom he has called “fat pigs,” “dogs,” “slobs” and “animals”) he hit back by threatening the questioner: “I’ve been very nice to you, although I could probably maybe not be, based on the way you have treated me. But I wouldn’t do that.”

[Kareem Abdul-Jabbar: In Donald Trump’s response to my essay, the bully proved my point]

Bad enough to alienate women in this way, but there’s even more insidious political crime here: attacking the First Amendment’s protection of a free press by menacing journalists. “I wouldn’t do that,” he said coyly. If you wouldn’t do it, why bring up that you could? For no other reason than to stifle other journalists who might want to ask tough but reasonable questions. If Americans learned that a leader in another country was threatening reporters, we would be outraged. Yet here it is. Right here. Right now.

Here are six times Republican presidential contender Donald Trump has insulted women, from Rosie O'Donnell to Ted Cruz's wife, Heidi. (Sarah Parnass and Nicki DeMarco/The Washington Post)

Later, after Trump had blamed her attitude on her menstrual cycle, Kelly went on what Fox says was a planned vacation. Nevertheless, Trump suggested he may have been the cause. What kind of candidate takes credit for bullying the media? And last week, Trump allowed Univision reporter Jorge Ramos to be ejected from a press conference for asking questions about immigration without being called upon. Ramos was later readmitted and permitted to ask about immigration, during which he said Trump could still deport immigrants compassionately. “I have a bigger heart than you do,” Trump replied. Trump’s non-specific answer to the question ended with a personal insult directed at the reporter.

[Dan Pfeiffer: Bernie Sanders isn’t Barack Obama and 2016 isn’t 2008.]

Trump’s vendetta against the press extended to the Des Moines Register. When the paper issued an editorial calling for Trump to withdraw from the campaign, he refused to give the paper’s reporters credentials to attend his campaign event in Iowa in July. He also called the paper “failing” and “very dishonest.” Other journalists he thinks have treated him harshly he refers to as “losers” or unintelligent, as if the definition of lack of intelligence is to not agree with him.

Attempting to bully the press to silence criticism of him is anti-American. He followed up this salvo on the First Amendment with a strike at the 14th Amendment, asserting that he’d like to deny those born in the country their citizenship. The biggest enemy to the principles of the Constitution right now is Trump.

Trump’s rationale for avoiding Kelly’s debate question – that neither he nor America has time for “political correctness” – taps into a popular boogeyman. The term “political correctness” is so general that to most people it simply means a discomfort with changing times and attitudes, an attack on the traditions of how we were raised. (It’s an emotional challenge every generation has had to go through.) What it really means is nothing more than sensitizing people to the fact that some old-fashioned words, attitudes and actions may be harmful or insulting to others. Naturally, people are angry about that because it makes them feel stupid or mean when they really aren’t. But when times change, we need to change with them in areas that strengthen our society.

It’s no longer “politically correct” to call African Americans “coloreds.” Or to pat a woman on the butt at work and say, “Nice job, honey.” Or to ask people their religion during a job interview. Or to deny a woman a job because she’s not attractive enough to you. Or to assume a person’s opinion is worth less because she is elderly. Or that physically challenged individuals shouldn’t have easy access to buildings. If you don’t have time for political correctness, you don’t have time to be the caretaker of our rights under the Constitution.

[Daniel Drezner: The most damaging part of Trump’s political rise.]

It’s easy to buy into the Trump mirage because his rising poll numbers indicate he’s actually doing well. But polls are historically misleading, and his supporters will eventually desert him. Many, such as Tom McCarthy in the Guardian, have laid out the statistical reasons Trump can’t win, complete with graphs that show polls from past presidential candidates who were doing even better than Trump at this stage of an election, only to fade into political irrelevance, like Rudy Giuliani, Howard Dean and Ross Perot. In 2008, Hillary Clinton was also a front-runner who unexpectedly got beat for the nomination by Obama.

Americans may flirt with the preppy life of the frathouse partier because he’s poked sacred cows, said stuff we all wish we could say (except that reason keeps us from doing it), and acted buffoonishly entertaining. But when you wake up the next morning and he’s saying you’re now in a four-year relationship, reason comes rushing in, and it is time for the “it’s me, not you” speech. With over a year until the elections, there are too many Republican hopefuls that dilute the polls. Once the herd thins out (Rick Perry seems out of money; Bobby Jindal out of breath; Huckabee out of touch), other candidates with more substance will have their voices heard. And when it comes down to just three or four candidates, Trump’s blustering inarticulation and dodging of questions will seem untrustworthy.

[UPDATE: Donald Trump responds to Kareem Abdul-Jabbar with a handwritten note.]

Although each absurd, uninformed or just plain incorrect statement seems to give Trump a bump in the polls, there are only so many times supporters can defend his outrageous assault on decency, truth and civility. Yes, a few will remain no matter what. (One 63-year-old woman told CNN that the Republicans were out to discredit Trump: “They twisted what the words were, because they’re trying to destroy him.” No one has to twist his words because what he says is twisted enough. He speaks fluent pretzel.) But voters will eventually see the light.

Meanwhile, Bernie Sanders faced his own challenge at a political event last month, when two African American women pushed in front of him to use the microphone to demand four and a half minutes of silence to honor the death of Michael Brown. Sanders left the stage and mingled with the crowd. Later, Trump criticized Sanders as being “weak” for allowing them to speak, but truly he showed grace under pressure by acknowledging their frustration and anger. Instead of bullying their voices into silence or ridiculing them as losers, pigs or bimbos, Sanders left. After all, it was not his event; he was a guest. Besides, his voice was not silenced, but came back booming even louder: The next day, Sanders posted a sweeping policy of reform to fight racial inequality. (The timing coincided with Michael Brown’s death and had nothing to do with the two women.)

Activists from Black Lives Matter and other groups interrupted Democratic presidential candidates Bernie Sanders and Martin O'Malley during a Netroots Nation event in Phoenix. (Sarah Parnass/The Washington Post)

The two approaches reveal the difference between a mature, thoughtful and intelligent man, and a man whose money has made him arrogant to criticism and impervious to feeling the need to have any actual policies. Trump threatens to run an independent campaign (he won’t; that’s a negotiating ploy). Trump is a last-call candidate who looks good in the boozy dark of political inebriation.

There’s a lot of complaining about the lengthy process in the United States of winnowing candidates, but this year has shown its great strength. It gives a wide variety of people the chance to have their voices heard, and it gives voters a chance to see the candidates over a period of time when their political masks slip. Some rise to the challenge, others deflate under the pressure of nothing to say.

Two roads diverged in a political wood, and one man took the road of assaulting the Constitution and soon will be lost forever. The other will be a viable candidate who, regardless of whether he wins the nomination, will elevate the political process into something our Founding Fathers would be proud of.