President Trump is only the latest man in the White House to see his plans, his governing coalition and his popular standing all at risk because of a racially charged issue.

In the days since he blamed the fatal violence in Charlottesville, Va., on people on "both sides" of the confrontation, Trump has been rebuked by key senators from his own party and deserted by members of his business advisory boards, (which he then said he disbanded). The mayor of Phoenix has asked the president to delay a planned visit.

The entire membership of the President's Committee on the Arts and Humanities has resigned, and Trump himself has decided not to attend the annual Kennedy Center Honors gala and not to hold the traditional gathering for the honorees at the White House.

By week's end, the president had also parted ways with chief strategist Steve Bannon, who had run Trump's campaign for the presidency last fall. Bannon had described himself as pleased with the president's handling of Charlottesville and his defense of Confederate statues.

Race — a subtext of American life

Race has been not only a recurring theme of American history but a subtext for much of our national life. The issue of slavery nearly broke up the convention that wrote the Constitution in 1787. It dominated debates in Congress for decades culminating in the Civil War in 1861. The treatment of former slaves and their descendants has roiled the social and political life of the nation ever since, forcing even presidents to examine their own hearts and question their own beliefs.

In some cases, the issue has engulfed a presidency, such as that of Abraham Lincoln, the Civil War president who held the Union together and issued the Emancipation Proclamation. More often, it has been in the background, as when Virginia-born Woodrow Wilson had a private White House screening of the 1915 film Birth of a Nation with scenes vilifying African-Americans and glorifying the Ku Klux Klan.

President Harry Truman was also a hereditary southerner, born in rural Missouri. But in the summer of 1948, Truman issued an executive order integrating the armed services:

"It is hereby declared to be the policy of the President that there shall be equality of treatment and opportunity for all persons in the armed services without regard to race, color, religion or national origin."

Southern Democrats were incensed and many would bolt the party that summer and fall, voting in November for the States' Rights Party candidate Strom Thurmond. Truman, however, stood his ground. "My forebears were Confederates," he replied. "But my very stomach turned over when I learned that Negro soldiers just back from overseas were being dumped out of Army trucks in Mississippi and beaten."

Truman's successor, President Dwight Eisenhower, grew up in Kansas and Texas and spent much of his life in the Army. He was not a fan of the 1954 Supreme Court decision against school segregation. But three years later, when nine Arkansas teenagers tried to integrate Little Rock Central High School in the face of an angry mob, President Eisenhower took up their cause.

Ike sent the legendary 101st Airborne Division to ensure that the students got through the jeering demonstrators. Delivering a then-rare televised address from the White House, Eisenhower said: "Our personal opinions have no bearing on the matter of enforcement; the responsibility and authority of the Supreme Court to interpret the Constitution are very clear."

Civil rights movement versus resistance

The civil rights movement gained momentum through the late 1950s into the early 1960s, but resistance remained in high places. The governor of Alabama, George Wallace, made his political name with his vow to enforce "segregation now, segregation tomorrow and segregation forever." In 1963, he stood literally "in the schoolhouse door" to block a black student's enrollment in the University of Alabama. President John F. Kennedy had walked a careful line between civil rights enforcement and the sentiments of Southern Democrats (Wallace was still a Democrat at the time). But in this instance he nationalized state guardsmen and took to TV in much the manner of Ike, six years earlier.

"I hope that every American, regardless of where he lives, will stop and examine his conscience about this," Kennedy said. "This nation was founded ... on the principle that all men are created equal, and that the rights of all men are diminished when the rights of one man are threatened."

But when Kennedy was assassinated five months later, it fell to his successor, Lyndon B. Johnson, to enact the civil rights legislation that had languished in Congress for decades. Johnson, a southerner from Texas, would sign the Civil Rights Act into law in 1964 and win that fall's election in a landslide.

But the following year he was concerned his agenda of Medicare, Medicaid and Great Society programs would suffer if he pressed too hard for a successor bill on voting rights. Events in Selma and Montgomery, Ala., forced his hand, however, and he went to Congress in March to demand action on what became the Voting Rights Act.

"As a man whose roots go deep into Southern soil, I know how agonizing racial feelings are," Johnson said, but he made it clear he was tired of hearing the old arguments and obfuscations. "The command of the Constitution is plain. There is no moral issue. It is wrong — deadly wrong — to deny any of your fellow Americans the right to vote in this country."

"A More Perfect Union"

In more recent times, we have seen our first African-American president struggle with the burden of racism and seemingly overcome it. Perhaps, Barack Obama's most famous speech of 2008 came in March of that year, after his association with an outspoken and controversial preacher threatened to derail his campaign.

He titled the speech " A More Perfect Union" in tribute to Lincoln, and at one point the biracial Obama said he could "no more disown my pastor than I can disown my own white grandmother, a woman who helped raise me, a woman who sacrificed again and again for me," but who also confessed her fear of black men she doesn't know on the street.

As president, Obama tried to confront the racial element of the gun violence that often dominated the news. One victim whose death resonated with the nation was Trayvon Martin, a black teenager in Florida shot by a self-appointed watchman in a gated community. "Trayvon Martin could have been me 35 years ago," the president said. "If I had a son, he'd look like Trayvon."

Later in his time in office, after a spate of police shootings of young black men, five Dallas policemen were killed by a sniper during an otherwise peaceful rally.

"We ask our police to do too much and ourselves to do too little," a saddened Obama said. "It's as if the deepest fault lines of our democracy have suddenly been exposed, perhaps even widened."

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