Actor Clint Eastwood's convention monologue, beside an empty chair, included a swipe at Biden.
"You're crazy, you're absolutely crazy. You're getting as bad as Biden," Eastwood cracked in his made-up conversation with Obama. "Of course we all know Biden is the intellect of the Democratic Party. Kind of a grin with a body behind it."
Biden himself has given as good as he gets.
He often is the loudest voice in the campaign's criticism against the Republican presidential nominee, former Massachusetts Gov. Mitt Romney. Biden led the charge against Romney in a series of speeches in battleground states last spring. He routinely bashes Romney and Ryan's assertions of promoting a "bold" plan on taxes and the Medicare.
"There is nothing gutsy about giving another trillion dollars in tax cuts to millionaires. There is nothing bold about turning Medicare into a voucher system," Biden said in Lordstown, Ohio, on Friday.
Another favorite topic of Biden's has been the administration's rescue of General Motors and Chrysler. Turning to Lordstown's sprawling GM plant, which has rebounded with the production of the compact Chevy Cruze, Biden took Ryan to task for blaming Obama for the closing of his hometown Janesville, Wis., GM plant, and he highlighted Romney's opposition to a taxpayer rescue of the U.S. car companies. The Janesville plant closed in 2008, before Obama's election.
"What they didn't acknowledge is Gov. Romney's position was 'Let Detroit go bankrupt,'" Biden said, referring to the headline on a Romney opinion piece in The New York Times in November 2008.
Democrats say the extra attention serves notice of Biden's abilities as a campaigner, along with his penchant for forming bonds with blue-collar workers through stories about growing up in hardscrabble Scranton, Pa.
He can move an audience with stories about watching his proud yet unemployed father forced to move to Delaware to find work or the death of his first wife and daughter in a car accident shortly after he was elected to the Senate in 1972. Such personal stories make a direct connection with union workers in Ohio or grandmothers in Florida.