Why would people consider sending united states troops to integrate a local school an action that goes against the principles of federalism?

President Dwight D. Eisenhower was the president that ordered the United States to integrate a local high school in Little Rock, Arkansas.He sent the troops in because of the state governor, Orval Faubus, refused to integrate the high school. He did this over the principles of federalism because the new policies that he asserted federal government over state government in certain situations. This was during the time he was promoting "the biggest peacetime construction of the United States." This was the federal highway system.