Democratic retirements are beginning to mount, after the announcement Monday that Rep. Bart Gordon (D-Tenn.) will not seek reelection next year. Gordon said in a statement that, after a quarter-century in Congress, it’s time to retire. “Every decision I have made in Congress has been with their best interests in mind,” he said. “I hope the people here at home feel that I have served them as well as their good advice and views have served me. “When I was elected, I was the youngest member of the Tennessee congressional delegation; now, I’m one of the oldest. In fact, I...