President Eisenhower decided to send troops to Little Rock because 9 African American children slipped into Central High school (witch was an all white school). After the children made it into the school a full-blown riot broke out. Governor Faubus had withdrawn the National Guard, so he appealed to Eisenhower for help, so Eisenhower sent troops into Little Rock.
Hope that helped
King Louis XVI was executed in 1793. The revolution ended when Napoleon Bonaparte took power in November 1799.
Nato was made up of democratic countries.