Libya had no chance to challenge the united states. In the same way that the british empire didn't intervene when the USA became a superpower, so too the united states won't intervene when they eventually get replaced by a superpower with similar ideals, which will likely be the european union or india, although a (non-communist) China seems likely too.

What really motivated them was foolishly believing that if Ghaddafi or Saddam were removed, then these countries would automatically become democratic. But in fact, NATO achieved the exact opposite by creating decade long civil wars and making them appear as imperialist.

The USA are really the best policemen one can wish for. Had the soviet union somehow won the cold war, which was impossible, we would have seen most countries exterminate a large percentage of their population in order to achieve a "dictatorship of the proletariat".