Donald Trump was elected to combat inflation, secure the border and counter the cultural excesses of the progressive left. Like any president, he’s expected to shift priorities when unforeseen circumstances surface. But if and when that happens, the president is obliged to explain himself to voters. The Trump administration’s problem is that much of the public is confused about the war, including many who agree that Tehran had it coming. As the American offensive in Iran approaches the two-week mark, too many voters are having difficulty making heads or tails of Washington’s goals and game plan. Earlier on Monday, Mr.…