PHOENIX – GOP Senate hopeful J.D. Hayworth, locked in a tough primary fight against Sen. John McCain, flubbed a key historical fact last week, asserting wrongly that the United States never declared war on Germany in World War II.The gaffe came as Hayworth responded Thursday at a Phoenix Republican club to a question about how the U.S. came to fight armed conflicts like those in Iraq and Afghanistan without formal war declarations by Congress. Hayworth, a former congressman, voted in 2002 to authorize the use of force in Iraq without such a declaration.