COLUMBIA, S.C. - Sen. Joe Biden, the Senate Foreign Relations Committee's incoming chairman, wants to get tough with Mexico, calling it an "erstwhile democracy" with a "corrupt system" responsible for illegal immigration and drug problems in the U.S. Biden, D-Del., was in Columbia on Monday in his first postelection trip to this first-in-the-South presidential primary state as he continues to line up support for his presidential bid. During a question-and-answer session before more than 230 Columbia Rotary Club members, Biden was asked about immigration problems. Biden, who favors tightening the U.S.-Mexico border with fences, said immigration is driven by money...