COLUMBIA, S.C. — Senator 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 America.

Mr. Biden, a Democrat of Delaware, was in Columbia on Monday in his first post-election 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, Mr. Biden was asked about immigration problems.

Mr. Biden, who favors tightening the America-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,” Mr. 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% of the population at the top, a very small middle class, and the rest is abject poverty.”

Unless the political dynamics change in Mexico and American employers who hire illegal immigrants are punished, illegal immigration won’t stop. “All the rest is window dressing,” he said.

An even bigger problem is illegal drugs “coming up through corrupt Mexico,” he said. “People are driving across that border with tons, tons — hear me — tons of everything from byproducts for methamphetamines, to cocaine, to heroine.”

Covering a variety of topics, Mr. Biden kept most of the crowd in their seats for an hour — twice as long as scheduled.

“I warn all of you, all of you making more than a million bucks — I hope you all are — I’m taking away your tax cut,” Mr. Biden said. “I’m not joking.”

The extra revenue would generate $75 billion a year and pay for a backlog in national security and local law enforcement programs, Mr. Biden said.

Mr. Biden’s appeal for bipartisanship captured Bruce Rippeteau, a former Rotary president who says he’s in the Genghis Khan wing of the Republican Party. He “was saying some important things in a nonpolitical way,” Mr. Rippeteau said.

Mr. Biden will lead the Foreign Relations panel because Republicans around the nation lost seats in the November 7 elections. That tide didn’t reach Republican-dominated South Carolina, where the GOP maintained its four U.S. House seats and Democrats kept their two.