People keep saying its ok for the US to attack Libya because the government there is killing people but?

Qaddafi has been killing his people for years. The rebellion against Qaddafi was peaceful until air strikes were brought in against the demonstrators. A very violent and evil strong man. If Obama tried to call the army to suppress demonstrators the Military command would remember that their oath was to defend the Constitution of the United States against all enemies, foreign and domestic. Also part of the oath is to obey LAWFULL orders of the officers appointed over them.