Petty mixed overall. Domestically a pretty fantastic president, but the atomic bombings is something that I'm skeptical of the claim that it was necessary and even more Japanese deaths would've occurred otherwise.
While there are debates over the effect of the atomic bomb on WWII, I don't think there is any debate on Korea. It was good that we tested relatively weak bombs and established the prohibition on nuclear weapons being used in small conflicts rather than glassing the Korean peninsula and/or starting WWIII by nuking China.