It looks like Vice President Joe Biden is dead serious about running for president in 2016. During a closed door speech before wealthy Democrats in South Carolina, Biden took a shot at the Clinton administration's economic policies in what was described as an "Elizabeth Warren-type" address.

The Hill:

Vice President Joe Biden gave a closed-door speech Friday to South Carolina Democrats that included a shot at the Clintons.

Biden, a potential 2016 candidate, said the unraveling of middle-class financial security began in "the later years of the Clinton administration," not under George W. Bush, CNN reported Saturday.

Speaking for more than thirty minutes at the VIP Capital City Club event in Columbia, S.C., he addressed the prominant group of attendees in the key presidential primary state.

In recent months, the vice president has focused on revving up liberals on issues of income inequality, as he prepares for a possible run against former Secretary of State Hillary Clinton, though many Democrats don't think he'd run against her.

Biden did not mention his own presidential ambitions Friday, but multiple sources described his speech as "populist" and high-energy, according to CNN. One attendee said it was an "Elizabeth Warren-type speech" blasting income inequality.

"He said we have some of the most productive workers in the world, but corporations are more concerned about their stockholders than they are about their employees," one attendee said. "He talked about how the fruits of labor go to stockholders, rather than to the people who are producing it. That the people making the money in this country are the corporations."

Another attendee described it as "a stem-winding, almost revival-type speech."

Biden's rare rebuke of the Clintons' economic policies, which some liberals view as too friendly to Wall Street, indicates how he'd possibly approach a 2016 campaign if he and Clinton square off in a primary.

If Biden wants to run to the left of Hillary, he will lose. But there's no doubt he has heard the whispers that Hillary Clinton may not run after all and it wouldn't hurt to position himself at first as a man of the left. He can always tack back toward the center as Barack Obama did in 2008.

Otherwise, his run would be an exercise in vanity - not unheard of for Biden but at his age - he would be 74 if he were to take office in 2016 - and the lack of excitement among activists at the prospect of him running, it would seem to indicate that Biden is keeping his options open in case Hillary doesn't run.