Which of the following is NOT one of the current threats to the USA in the nuclear arena?

The focus of current nuclear threats to the USA typically includes nations that possess nuclear capabilities or are actively pursuing nuclear weapons programs. North Korea, China, and Russia are recognized as significant threats due to their established nuclear arsenals and geopolitical behaviors that could potentially put U.S. interests at risk.

North Korea has demonstrated its nuclear capabilities through various tests and aggressive posturing, while China and Russia are both recognized powerhouses in the nuclear arena with substantial arsenals and strategic doctrines that directly challenge U.S. security interests.

Turkey, while a member of NATO and possessing strategic importance, does not currently have an independent nuclear weapons program in the same way that the other three countries do. Instead, Turkey's nuclear policy is heavily tied to its association with NATO's nuclear sharing arrangements, which differentiates it from the active nuclear threats posed by the other nations mentioned. This context illustrates why Turkey does not represent a direct nuclear threat in line with the current challenges faced by the U.S.