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In 1957, the state of Arkansas refused to honor a federal court order to integrate their public school system stemming from the Brown decision. Eisenhower demanded that Arkansas governor Orval Faubus obey the court order. When Faubus balked, the president placed the Arkansas National Guard under federal control and sent in the 101st Airborne Division. They escorted and protected nine black students' entry to Little Rock Central High School, an all-white public school, for the first time since the Reconstruction Era. Martin Luther King Jr. wrote to Eisenhower to thank him for his actions, writing "The overwhelming majority of southerners, Negro and white, stand firmly behind your resolute action to restore law and order in Little Rock".

What Arkansas militia unit did Eisenhower federalize in 1957?
Arkansas National Guard