There is no way to put it other than being blunt about it. US President Donald Trump appears ready to take the world back to the dark Cold War era of the 1950s and 1960s with his uninformed foreign policy pronouncements. He has already turned his back on the Paris climate deal. He has damaged ties with Mexico. On Nafta, he has left America's allies fretting. On North Korea, his endless tweets have been a clear demonstration of the incongruity of his presence in the White House.
And now he is determined to tear up the Iran nuclear deal because he thinks Tehran is not living up to it. The problem is not Iran, which has since it agreed to the deal scrupulously been maintaining its side of it. Neither is the problem with the other global powers which persuaded Iran to accept the nuclear arrangement. The problem is Trump himself and the chaotic, incoherent administration he presides over. He may one of these days decertify the Iran agreement.
The loss will be that of the US in a couple of ways. First, the other countries and the European Union will not go along with him, which will be a fresh rebuke to him. Second, any rash US action against Iran could well provoke Tehran into rejecting the agreement altogether and going back to the position it held before signing up to it.
That can only mean a new setback for Trump's America. With North Korea defying him pointedly with its missile launches, the US leader has been unable to do much beyond attempted bullying and name calling. Now if he moves against Iran, he can expect another adversary that will go after him with bare knuckles. Trump, in that situation, may not feel embarrassed. But America will.