DALLAS — Financial concerns have been the most pressing issue for voters in four of the six previous midterm elections of this century. But with the war in Iran and tariffs driving up gas prices, inflation and mortgage rates, the worries feel deeper, more desperate and decidedly center stage in the final days of the hard-fought campaign that will decide control of Congress.

Democrats are hammering President Donald Trump for starting a war with Iran and instituting tariffs that have driven up prices, while Republicans are insisting the fundamentals of the economy are stronger than before they took power two years ago.…