Conservative radio host Rush Limbaugh said Sunday he believes former Vice President Joe Biden appears to be the front-runner in the race for the Democratic Party's 2020 presidential nomination in which the players are trying to "out-extreme" each other.

"The front-runner would probably be right now Joe Biden. 77-years-old, plagiarist, nicknamed 'Plugs.' I think he's the guy that they are probably all thinking is the leader in the polls right now," Limbaugh said.

"But it's going to be very crowded. They are going to be knocking each other off, that will be fun to watch," he added. "Incumbency carries with it a lot of power and I think they are convinced they've already won this election, like they were convinced in 2016. They're getting way ahead of the game and I don't think it's going to be as easy as they think."

Although the influential radio pundit nicknamed Biden "Plugs" in reference to hair restoration work, Trump — famous for belittling rivals with nicknames — reportedly favors the moniker " Creepy Joe," which references Biden's reputation for physical touching women.

Biden has not declared his candidacy for the Democratic nomination, but polling shows he leads the expansive field of Democratic and independent politicians who have declared or are considering a bid.

Limbaugh, who encouraged throngs of conservative voters to meddle in the 2008 Democratic primary, said he expected the 2020 contest to feature increasingly left-wing policies.

"They are so convinced they are going to win that so many are running," he said. "And they are going to be in a contest to see who can out-extreme the other: Who can move the country furthest to the left the soonest? It's going to be very entertaining to watch. I hope it is eye-opening for the American people."