Scrapping the deal with Iran could embolden its hardliners

FOR three years American forces have quietly worked in tandem with Iran’s Revolutionary Guard Corps (IRGC) to roll back Islamic State in Iraq. It was as unlikely an alliance as any imaginable. A decade ago IRGC operatives orchestrated attacks on American soldiers in Iraq. Crowds still gather in Iran to chant “Death to America!” Yet as American planes struck from the sky, Iran managed the advance on the ground. All this may be about to change.