Of all this election year's intrigues, the one I find most befuddling is not billionaire Donald Trump’s anti-Democratic thunderous march toward the Republican presidential nomination, but the robust support the Democratic Party establishment is receiving from African-Americans.

In a period rife with discontent with this country’s longstanding institutional racism, who would have thought that African-Americans would be the firewall that slowed and perhaps - given the electoral math - derailed independent Sen. Bernie Sanders’ bid for the party’s presidential nomination.

But in helping to propel former secretary of state Hillary Clinton to a 47.5-point victory over Sanders in the South Carolina primary, African-Americans, and primarily those over 30 years old, have decidedly sided with the party’s establishment base.

This is important to note, since an implicit message in the rise of the Black Lives Matter movement is that establishment politics has at best been accommodative to the lingering injustices faced by African-Americans and particularly the injustices of the nation’s criminal justice system.

The rationale given by African-American leaders in supporting Ms. Clinton is that she has always been there for them, while Mr. Sanders, despite his strong civil rights record, is more of a Johnny-come-lately bearing unrealistic expectations.

Ms. Clinton, they say, has the more realistic chance of winning the presidency because her progressive views are not as extreme as those of Mr. Sanders. But besides Mr. Sanders' support of a single-payer health care system and tuition-free public colleges, the only difference between the two candidates' platforms is the issue of trust.

Ms. Clinton might be the most talented and most experienced of all the presidential candidates still viable, but is she trustworthy? What is the prize that she seeks— the presidency or the opportunity to make a difference in the lives of ordinary Americans?

If we look to her past to answer that question, it would appear that winning the presidency is her greatest motivation and ambition. If that is the case African-Americans could be in for a rude awakening should she become president.

One thing the past tells us is that Ms. Clinton is a politician at her core, always willing to do what it takes to win. We saw this during her 2008 presidential nomination battle with then Sen. Barack Obama, when many African-Americans felt she resorted to a number of racial dog whistles in trying to stall Mr. Obama’s push to the nomination.

But even more worrisome is the destructive impact her husband Bill Clinton’s presidency has had on African-American families.

According to the Justice Policy Institute, federal and state prison populations rose more under Mr. Clinton than under any other president, with more people jailed in federal prisons under Mr. Clinton than under Presidents George Bush and Ronald Reagan combined.

To show how tough he was on crime, Mr. Clinton supported measures that during his eight-year tenure swelled the total prison population by 673,000 people, 235,000 more than under Mr. Reagan.

Jeff Stein, writing for Salon, summed up Mr. Clinton’s push to out-tough Republicans on crime as follows:

"The 'New Democrat' spoke on the campaign trail of being tougher on criminals than Republicans; and the symbolism of the (Ricky) Rector execution was followed by a series of Clinton 'tough on crime' measures, including: a $30 billion crime bill that created dozens of new federal capital crimes; new life-sentence rules for some three-time offenders; mandatory minimums for crack and crack cocaine possession; billions of dollars in funding for prisons; extra funding for states that severely punished convicts; limited judges’ discretion in determining criminal sentences ...”

He also noted that “there is very strong evidence that these policies had a small impact on actual crime rates, totally out of proportion to their severity,” and that the policies “contributed to the immiseration of vast numbers of black (and also white) Americans at the bottom of the economic ladder.”

Some will say she is not her husband, but she was an active promoter of Mr. Clinton’s criminal justice reform measures. During a stump speech in support of those measures in 1996, she invoked a characterization of young African-American men that spoke to their dehumanization in the criminal justice system.

“They are not gangs of kids anymore,” she said.

“They are the kinds of kids that are called superpredators — no conscience, no empathy. We can talk about how they end up that way, but first we have to bring them to heel.”

Compare those remarks with Mr. Sanders' then critique of the same crime bill.

“It is my firm belief that clearly, there are some people in our society who are horribly violent, who are deeply sick and sociopathic, and clearly these people must be put behind bars in order to protect society from them.

“But it is also my view that through the neglect of our government and through a grossly irrational set of priorities, we are dooming tens of millions of young people to a future of bitterness, misery, hopelessness, drugs, crime, and violence.”

Mr. Sanders’ might not be the decorated civil rights activist black leaders claim Ms. Clinton to be, but he has been constant in his convictions. Ms. Clinton, on the other hand, has a proclivity to twist and turn in the political wind, which is why I don’t think African-Americans' leap of faith in supporting her candidacy is justified.