COLUMBIA, South Carolina (AP) -- 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-Delaware, 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 in low-wage Mexico.

"Mexico is a country that is an erstwhile democracy where they have the greatest disparity of wealth," Biden said. "It is one of the wealthiest countries in the hemisphere and because of a corrupt system that exists in Mexico, there is the 1 percent of the population at the top, a very small middle class and the rest is abject poverty."