Most voters think President Trump made the wrong decision to go to war with Iran, a New York Times/Siena poll found, leaving the Republican Party on rocky political footing heading into the midterm elections as his approval rating sinks and economic concerns rise.Majorities of voters said that the war was not worth the costs and held deeply pessimistic views about the economy.Mr. Trump’s approval rating — a key historical predictor of how a president’s party will fare in an election — has sunk to a second-term low in Times/Siena polls of 37 percent amid the deeply unpopular Middle East conflict....