Isolationism would be a preferable attitude for the US (and all nations) to take... At least compared to their current position.
International intervention is practically always self-interested in nature. The US and UK for instance do not interfere in the affairs of other countries unless they can gain something from that interference.
The number of instances in history where a nation has sent troops into another country for altruistic reasons can literally be counted on one hand.
Therefore, while being BENEVOLENT would be optimally moral... being isolationist would certainly be an improvement, since we are effectively malevolent, currently.
[FW] Spider AL
Hewwo, meesa Jar-Jar Binks. Yeah. Excusing me, but me needs to go bust meesa head in with dissa claw-hammer, because yousa have stripped away meesa will to living.