Washington —Americans are growing more pessimistic about the US economy as the war on Iran continues to roil markets, with sentiment falling across all income groups — including the wealthiest. Gas prices across America have already surged since the onset of the conflict. Long-run inflation expectations serve as a proxy for Americans’ confidence in the Fed’s ability to rein in price increases. What souring sentiment means for the economyDeclining consumer sentiment has not translated to weaker spending in recent years. If the Iran war drags on for months, the outlook could quickly darken, setting off a downward economic spiral as falling stocks give way to weaker spending and, ultimately, a recession.