"I would not be afraid to attack back," said Schumer, who chairs the Democratic Senate Campaign Committee, in an interview with Politico.
"I thought the Britney Spears commercial was powerful," Schumer said, referring to McCain's television ad casting Obama as a vapid "celebrity."
"They're trying to say, 'He's not one of us,'" Schumer said.
"I would answer back hard. What do you mean he's not one of us? It's John McCain who wears $500 shoes, has six houses, and comes from one of the richest families in his state," Schumer said. "It's Barack Obama who climbed up the hard way, and that's why he wants middle-class tax cuts and better schools for our kids."
Obama's campaign responded to McCain's barrage by accusing him in television ads and press releases of taking the "low road," while casting Obama as above such attacks on his opponent's character.
The strategy has produced some questions in Democratic circles as to whether Obama shouldn't be hitting back more personally - but Obama's aides argue that the perception that McCain is running a traditional, negative campaign is damaging McCain's reputation for high-minded independence.
Schumer didn't directly criticize Obama's strategy, but he argued for a higher-velocity response.
"When they say,'He's not one of us,' you don't say, 'Here's our plan on health care,'" he said.
Schumer is currently promoting the paperback edition of his book "Positively American," which argues for a Democratic agenda pitched around a new set of bread-and-butter issues and government activism on behalf of middle class voters. But he argued that Obama will best be able to make his case on issues if he's also willing to slap back on matters of character.
"McCain's an unappealing candidate," Schumer said. "McCain's done great things for our country, but he doesn't particularly empathize with the plight of the average person."
Schumer argues in a new preface to his book that Americans' economic insecurity could make 2008 a re-aligning landslide.
"This election has the potential to effect the kind of paradigm-shifting change that occurs once in a generation," he writes, comparing the vote to Franklin Roosevelt's rise in 1932 and Ronald Reagan's in 1980. "If it's decided by issue and policy offerings, this election might just be the one that creates a political majority for a generation."
Schumer, who supported his junior New York senator, Hillary Rodham Clinton, in the primary, said he never underestimated Obama's strength.
"He's an amazingly capable person, and I think everyone in the Senate knew that," he said.
"It was a close race, a hard-fought contest, I think either one of these candidates would have made a great president and would beat McCain," he said.
Though Schumer seemed to be urging Obama to hit back harder, he said Americans' general unhappiness at the state of affairs would dampen the effect of Republican attacks on his character and readiness to lead.
"I think there's a real chance that Obama gets 300 electoral votes," he said. "This is a change election and the more people get to know him and see him the better it will be."