Vice President Biden delivered an enthusiastic speech brimming with populist notes in Iowa on Wednesday, including an impassioned appeal to bridge the gap between rich and and poor.

"One percent of the population shares 20 percent of the entire income of the United States," said Biden. "What that's meant is that the middle class and the poor have taken a hit. They share a lot less."

Biden made his remarks at a kick-off rally for the Nuns on the Bus “We the People, We the Voters” bus tour in Des Moines. The vice president visited Iowa, which weighs in first in the presidential nominating process, in an official capacity. But the trip is likely to stoke a new round of chatter about whether or not he'll make another presidential bid in 2016.

With his sleeves rolled up, Biden touched on immigration, taxes, voting rights and regulating Wall Street banks, all issues that resonate with liberal activists. He argued that the wealthiest Americans should be concerned about income inequality because of what it does to the economy.

"Income inequity brings a drag on economic growth," said Biden. "Even Wall Street is concerned about this growing gap between the middle class, the poor and the wealthy."

Biden said he was "not making a moral judgement" about income inequality, but rather encouraging Americans to explore how it happened.

"We should be asking the question why the CEOs now make 333 times more than their average employee, when back when Reagan was elected president, they made 42 times as much.

On immigration, Biden encouraged lawmakers to pass comprehensive reform. The people who come to America "are the people who have the most courage," he said

"Some people think you sit around a table in Guadalajara and say, 'You know what, why don't we sell everything, give it to a coyote and go to a country that doesn't want us,'" Biden said. "Boy, won't that be fun."

Biden slammed GOP efforts in state legislatures to "curtail the right to vote."

"There used to be a consensus," he said. "Democrats and Republicans. It was Republicans who fought for motor voter registration. It was Republicans who fought. What has happened here? We lost the consensus."

Even Democrats, Biden acknowledged, need to do a better job talking about the problems facing the middle class, a part of American society he said is "not a number," but a "value set."

Biden praised the Nuns on the Bus for campaigning for health-care reform and against the budget proposed by Rep. Paul Ryan (R-Wis.).

"This isn't a populist rant," concluded Biden. "This is about how you build America."