In the nearly three weeks since President Donald Trump struck Iran, conventional wisdom has set in that his base is sticking with him on the war. It’s true that Trump’s base hasn’t ditched him in huge numbers — and an overwhelming number of MAGA supporters, especially, say they support the war. The opposition from the likes of Tucker Carlson, Marjorie Taylor Greene, Megyn Kelly and other influencers hasn’t translated to wide swaths of the GOP base itself. But Trump has alienated some significant portions of his base, and he’s risking alienating more. A fresh batch of polling in recent days...