Americans celebrating Martin Luther King Day today should be proud of the incredible progress made since the civil-rights leader’s birth 87 years ago. At the same time, we should lament one of President Obama’s greatest failures.

The last Democratic president and the last Republican president both managed race relations more effectively than Obama has. Seven years after American voters made history by electing the country’s first black president, racial tensions have worsened.

It didn’t rank on Obama’s one-item list of his “few regrets” during his State of the Union address. But signs of Obama’s failure are on our streets, on our campuses and among our leaders, left and right.

“Ferguson” has become shorthand for African-American fury objecting to insensitive white cops harassing young blacks. The “Black Lives Matter” movement has spilled into American campus culture, as privileged kids attending the world’s finest universities bemoan their alleged oppression — bullying anyone who challenges them.

This black backlash has prompted a white backlash, personified by Donald Trump. Every justifiable police shooting called “racist,” every Halloween costume labeled politically incorrect, every reasonable thought censored makes Trump look like America’s last honest man.

Amid this tension, Obama has been disturbingly passive — even during America’s first serious race riots since 1992. He acts like a meteorologist observing the bad weather, not a president able to shape the political climate.

How embarrassing that Obama’s most memorable act of presidential leadership on race may end up being inviting a black professor and a white cop to the White House for his 2009 “beer summit.”

By contrast, consider Bill Clinton’s proactive attempts to reconcile blacks and whites. In November 1993, Clinton preached in Memphis against black-on-black crime, urging African-Americans to tackle the problem from “the inside out,” through family and community, not just from the “outside in,” meaning government.

His crime-fighting package and welfare reform promised poor blacks safe streets and dignified employment, without “dog whistling” — blaming blacks to woo whites. In 1997, Clinton and Arkansas Gov. Mike Huckabee welcomed into Little Rock High School the “Little Rock Nine,” the blacks blocked in 1957 at the schoolhouse door. When one of them — now older, grayer, heavier but freer — stumbled, the Republican governor and the Democratic president tenderly caught her.

The 1990s had racial clashes, too. Still, although it was foolish to call Clinton our “first black president,” Clinton reassured blacks that they had a friend in the White House, while encouraging blacks and whites that we could create Dr. King’s moral America.

Even though only 9 percent of black voters chose George W. Bush in 2000, his presidency’s biggest controversies dodged race, focusing on terrorism, the Iraq war and the economic meltdown. Bush’s outreach to Arab-Americans ‪after 9/11 calmed many African-Americans — just as Trump’s anti-Muslim demagoguery today offends many blacks.

Bush integrated his administration naturally, appointing Secretary of State Colin Powell and National Security Adviser Condoleezza Rice because of their smarts, not their race. Obama’s election in 2008 was a natural progression of the Bush era’s racial progress.

Last August, Gallup reported that “Americans rate black-white relations much more negatively today than they have at any point in the past 15 years.” White optimism dropped 27 percent in the last two years, with black optimism down 15 percent.

Since at least the presidency of Franklin D. Roosevelt, managing racial tensions has been an important yardstick of presidential success. It’s fair to ask: What has Obama done to reconcile blacks and whites? How has he helped beyond being America’s first black president? And yes, expectations are greater for him, even as the politics are more volatile.

After this fall’s volatility, quickly calling for unity in this State of the Union was feeble. While championing America’s redemptive dynamism, Obama should also recalibrate the debate, acknowledging the diverging fears and anger of both blacks and whites.

Only once the atmosphere changes can he start pitching solutions — from the “inside out” and the “outside in” — to improve race relations by next Martin Luther King Day, which will fall just days before his presidency comes to a close.

Gil Troy is a professor of history at McGill University and the author, most recently, of “The Age of Clinton: America in the 1990s.”