"Every successful revolution puts on in time the robes of the tyrant it deposed." - Barbara Tuchman
If you've been following me for a while, you've probably heard me use that Barbara Tuchman quote before. It's an apt description for the ways in which revolutionary leaders soon find themselves administering the very systems of power they once decried and often committing the same sins that led them to revolt in the first place.

The American Revolution, which began with the self-evident declaration that "all men are created equal," quickly found a way to deny such basic equality to African-Americans.

Vladimir Lenin's Bolshevik Revolution, which sought to bring power to the Russian people in 1917, devolved into a totalitarian state that repressed the very people it claimed to liberate.

It's easy to politic. It's not as easy to govern. And it's one thing to campaign for change, but it's quite another to implement it. That's the dilemma that's faced every agent of change in this country from Thomas Jefferson to Barack Obama, and that's the dilemma that now faces New York City Mayor Bill de Blasio.

Elected last year after he aired clever TV campaign ads highlighting his multiracial family and his son Dante, Mayor de Blasio is now coming under fire for the current practices of the same NYPD he pledged to reform.

It started with the death of Eric Garner, a 43-year-old African-American who died last month after a police officer placed him in a chokehold that violates NYPD's own policies. Then stories emerged of other choking incidents involving the police. And recently video emerged of a pregnant woman who appeared to be choked by police officers.

All that put the mayor and the police commissioner on the defensive, as they struggled to express their condolences to the family of Eric Garner, denounce the use of banned chokeholds, maintain their support for the NYPD and still reaffirm their commitment to changing unfair police policies that disproportionately target Blacks and Latinos.

Finally, in a much-publicized meeting on Thursday, Rev. Al Sharpton politely called the mayor to live up to his promise. "Your ability to show some sensitivity has raised hopes and given you the plurality that you got to become mayor," Sharpton told de Blasio. "But now you’ve got to go from hope to actuality," he said.

Then, in a provocative exchange that landed on the covers of all three morning tabloids today, Sharpton invoked de Blasio's son: "If Dante wasn’t your son, he’d be a candidate for a chokehold," Sharpton told the mayor.

Under normal circumstances, Sharpton's statement might have crossed the lines of seemingly fair political discourse. Families, especially children, are generally considered off limits in political attacks. But this comment was different. Sharpton wasn't so much launching an attack as issuing a reminder to the mayor.

Remember, this was the same mayor who campaigned with his son and plastered images of his son (and his huge afro) all over the media last fall. Dante even recorded a campaign ad where he spoke about the NYPD's controversial "stop-and-frisk" policies that typically focused on young Black men like himself.

"He's the only one that will end a stop-and-frisk era that unfairly targets people of color," Dante told us. "Bill de Blasio will be a mayor for every New Yorker, no matter where they live or what they look like." Then came the kicker: "And I'd say that even if he weren't my dad."

As someone who has been unfairly targeted and stopped by the police myself, I understand why Rev. Sharpton is so outraged. Black men in New York City live in a climate where we are constantly suspected of wrongdoing. This was the argument that made candidate Bill de Blasio such a compelling champion for police reform last year. And that's why we expect more from this mayor than we got from Mayors Giuliani or Bloomberg.

He's only been in office seven months, but the clock is ticking. As of now, we still have hope that Mayor de Blasio will deliver.

Keith Boykin is a New York Times best-selling author and former White House aide to President Clinton. He attended Harvard Law School with President Barack Obama and currently serves as a TV political commentator. He writes commentary for BET.com each week.

The opinions expressed here do not necessarily reflect those of BET Networks.

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