On the verge of what is expected to be a long reelection year, US Senator Scott Brown yesterday declared himself the underdog in a battle against likely Democratic opponent Elizabeth Warren, but expressed confidence that he can win a full six-year term by persuading voters that she is too liberal and uncompromising on a host of issues. The senator’s decision to talk about the pending Senate campaign comes after months of general silence from him and his aides during which Warren has emerged as a major threat to his reelection effort.