You’re Republican Senator Scott Brown. As you face a tough reelection battle in a state that favors Democrats, you must be thinking: What was I thinking when I agreed to ban outside attack ads during my showdown with Elizabeth Warren? Across the country, groups sympathetic to Republican candidates are pouring millions into a barrage of ads aimed at undermining their Democratic challengers. So far, Massachusetts, the setting for the hottest Senate race in the nation, is not part of the action.