ST. LOUIS • Listen up, Nation.

Comedian Stephen Colbert leapt onto the stage at Washington University on Saturday with his trademark faux right-wing bravado, to a frantic reception by about 1,200 college students from around the globe.

In a packed fieldhouse, he greeted them as future leaders who went to college to change the world — “and, one assumes, to hook up.”

They were also here to participate in the sixth annual Clinton Global Initiative University, former President Bill Clinton’s project to improve the world with invention and innovation.

Colbert, appearing at the end of the two-day CGI University program, was the sugar with that medicine.

“It’s important that this is fun,” former first daughter Chelsea Clinton told the gathering earlier. She said Colbert’s appearance was meant to make the program about more than “a lot of earnest do-gooders.”

After Colbert brought the students up to date on modern developments in the post-Twitter world (“All human thought has been limited to 140 characters”), he introduced Bill Clinton as “the most beloved former president other than Martin Sheen.”

“My first question for you,” Colbert demanded of Clinton, suspiciously, “is: Why help other people?”

As Clinton tried to answer, Colbert pulled out a hand-held mirror and began addressing Clinton through his reflection. Colbert explained that Clinton is “the Medusa of political persuasiveness,” and he needed the mirror in order to thwart the ex-president’s liberal spell.

Colbert — whose over-the-top patriotic television character routinely addresses his audience as “Nation” — shed that character partway through the talk. He put on a new jacket to drive home the point, and delved into more serious discussions with Clinton.

“Do you ever get heartbroken watching what’s happening in Washington today?” Colbert asked. Clinton responded, “I do.”

But he then reminded the audience that his own tenure was beset by “bitter partisanship” at various times. “They shut the government down twice.” He described the Washington political process as “pushing a rock up a hill.”

“What I thought would happen after this (2012) election, when the president won,” would be a thawing of partisan bickering, Clinton said. That that hasn’t yet happened, he said, and “makes us look small to ourselves and the rest of the world.”

When Colbert asked Clinton about his relationship with other former presidents, Clinton confided that George W. Bush initially “couldn’t stand me because I’d beat his father” in 1992.

“I don’t blame him. He loves his dad, I beat his father, it’s OK,” said Clinton. He said their relationship warmed after they worked together on an anti-AIDS program.

Colbert’s character from “The Colbert Report” never did completely leave the stage.

When Colbert asked what Clinton thought was the world’s most pressing problem, Clinton responded that it’s the “disparity in treatment between boys and girls and women and men.”

“I would have gone with ‘ATM fees,’” Colbert responded.

Clinton founded the Clinton Global Initiative in 2005 to bring political and business leaders and others together to address global problems in areas such as the environment, energy and health.

CGI and its spinoff projects, including CGI University, use what organizers call “commitments to action” to address these issues. These are specific plans by the participating person or entity, generally including possible sources for funding.

CGI University was founded in 2007 as a spinoff of CGI. It uses the same “commitment to action” model as CGI but is geared toward college students.

This year’s program, the sixth, at Washington University, included a talk with Twitter founder and St. Louis native Jack Dorsey, who described his hyper-popular social network in terms of its ability to spawn a global conversation.

Clinton admitted during Saturday’s conversation that he seldom goes on Twitter.

“I’m thinking of doing it more ... after talking to Jack,” Clinton said. He said he is “insecure” about tweeting. “What if you tweet and nobody tweets back?” he asked.

Colbert is the second Comedy Central alum to be featured at CGI University. Jon Stewart, host of “The Daily Show,” spoke at last year’s event at George Washington University in Washington, D.C.

CGIU has also been held at Tulane University in New Orleans; the University of Texas at Austin; the University of Miami in Coral Gables; and the University of California at San Diego.

Follow Kevin McDermott on Twitter @kevinmcdermott

Kevin McDermott is a reporter for the St. Louis Post-Dispatch.