Fifty years after federal troops escorted Terrence Roberts and eight fellow black students into an all-white high school, he says the struggles over race and segregation still are unresolved.

"This country has demonstrated over time that it is not prepared to operate as an integrated society," said Roberts, who is a faculty member at Antioch University's psychology program.

He and the other students known as the Little Rock Nine will help the city observe Central High School's 50th anniversary this week with a series of events culminating with a ceremony featuring former President Bill Clinton.

Get Breaking News Delivered to Your Inbox

For three weeks in September 1957, Little Rock was the focus of a showdown over integration as Gov. Orval Faubus blocked nine black students from enrolling at a high school with about 2,000 white students. Although the U.S. Supreme Court had declared segregated classrooms unconstitutional in 1954 - and the Little Rock School Board had voted to integrate - Faubus said he feared violence if the races mixed in a public school.

The showdown soon became a test for then-President Dwight D. Eisenhower, who sent members of the Army's 101st Airborne Division in to control the angry crowds. It was the first time in 80 years that federal troops had been sent to a former state of the Confederacy.

Yet, half a century later, there are signs of progress and strife in Arkansas' largest school district, which is now 70 percent black.

A federal judge ruled this year that the 27,000-student district was unitary, or substantially integrated, and ordered the end of federal desegregation monitoring. The school now has a nearby museum for the Little Rock crisis, and statues of the nine brave students stand on the grounds of the state Capitol.

But race still divides the school board, which has a black majority.

In 1957, Roberts, Carlotta Walls LaNier, Melba Patillo Beals, Elizabeth Eckford, Ernest Green, Gloria Ray Karlmark, Jefferson Thomas, Minnijean Brown Trickey, and Thelma Mothershed Wair were determined to get a good education.

"I really didn't understand at 14 we were helping change the educational landscape here in America," LaNier recalls. "All we wanted to do is go to school."

When Faubus pulled Arkansas National Guard members from blocking nine students from entering the school, an inflamed crowd gathered to keep the black students out.

Relman Morin, an Associated Press reporter standing outside the school at the time, described the chaos as a "human explosion" when the nine students were slipped inside during a melee.

Eisenhower was shocked at the outbreak of violence.

"Cruel mob force had frustrated the execution of an order of a United States court, and the governor of the state was sitting by, refusing to lift a finger to support the local authorities," Eisenhower later wrote, according to David A. Nichols, author of "A Matter of Justice: Eisenhower and the Beginning of the Civil Rights Revolution."

Eisenhower signed a proclamation approving the use of federal troops to enforce U.S. District Judge Ronald Davies' desegregation order and the students entered Central High under armed escort Sept. 25, 1957.

"That was a turning point in history because it said that, when push comes to shove, two of the three branches of American government will respond on behalf of integration as part of the fundamental American heritage," said historian Taylor Branch, Pulitzer-Prize winning author of "Parting the Waters" and other books about the civil rights movement. "It said that segregation is not compatible with American ideals."

Green, the first black person to graduate from Central, said he had studied the history of other black trailblazers at the time but didn't think he would join their ranks.

"We saw ourselves as groundbreakers in breaking tradition," said Green, who served as an assistant Secretary of Housing and Urban Affairs under President Jimmy Carter. "But I don't see that any of us thought we would be part of the civil rights legacy."Despite the torment and legal battle, eight of the nine black students completed the school year. Trickey said she was expelled when school officials found her at fault in a run-in with girls she called "white trash."

The following school year, Faubus closed the schools in Little Rock. He was re-elected governor the next month.

During the "lost year" of the closed schools, some students studied their textbooks at home while others for a time took classes by television. Schools surrounding Pulaski County were jammed with transfer students, and Memphis, Tenn., announced that fall that it couldn't take any more transfers from Little Rock.

The schools reopened in 1959, partly because of an effort by white businessmen who realized that the crisis was hurting their community and the economy.

"Basically, what they were interested in was getting Little Rock off the front pages and salvaging her image. Again, they weren't interested in justice or racial change," said Elizabeth Jacoway, author of "Turn Away Thy Son," a history of Central's desegregation.

Trickey and the other nine said they're frustrated with the school system nationally, not just in Arkansas, that they see as still widely segregated.

"We're still living segregated lives based on culture and language," said Trickey, who now works as a gender and social justice advocate. "Here we are in 2007 and we're still playing the same game."