As Senator Biden prepares to face off against Governor Palin on Thursday night in the campaign’s lone vice presidential debate, Democratic strategists have a few words of advice for the lawmaker of Delaware: Ignore the Alaskan.

Mr. Biden’s 35 years in the Senate dwarf Ms. Palin’s single month of experience on the national stage, but Democrats are worried that his penchant for verbal missteps and his occasionally aggressive style could be a liability as he faces only the second woman to serve as a major party nominee for the vice presidency.

“His goal is to ignore Palin and focus on connecting with voters sitting in their living rooms by making clear he is indeed one of them — an uncommon, common man,” a Democratic strategist who served as an aide to Vice President Gore during the 2000 campaign, Christopher Lehane, said.

The two running mates will meet in St. Louis this week for what is perhaps the most eagerly anticipated vice presidential match-up in recent memory, and the debate is fraught with risk for both candidates.

After winning rave reviews for her debut speech at the Republican National Convention early in the month, Ms. Palin has struggled as she has come under increased scrutiny from the press. Polls have shown voter concerns about her readiness for the job, and she has been widely derided in recent days for the nearly incomprehensible response she offered when CBS’s Katie Couric asked her to explain her claim that Alaska’s proximity to Russia and Canada gave her foreign policy experience.

Those stumbles have raised the stakes for Thursday’s debate, but Democrats are offering another reason why Mr. Biden should avoid trying to exploit Ms. Palin’s lack of experience — he may not need to.

“Let the facts, the records, and the ideas speak for themselves, and more than likely Governor Palin will expose herself as unqualified for the job,” a Democratic consultant, Daniel Gerstein, said. “If he has the right tone, there’s no way he can lose this debate.”

Mr. Biden needs only to look to Senator Clinton’s Senate race in 2000 against Rick Lazio to see the perils of a male appearing overly confrontational with a female candidate. During their debate, Mr. Lazio walked over to Mrs. Clinton’s podium to ask her to a sign a pledge against accepting so-called soft money campaign contributions. The move backfired, as the Republican congressman looked as if he were physically intimidating the then-first lady.

“Debating with a woman is entirely different than anything you will ever do,” a Democratic consultant who worked for President Clinton’s re-election bid in 1996, Hank Sheinkopf, said. He said Mr. Biden needed to avoid doing anything that would appear “glowering” or “menacing” and would engender sympathy for Ms. Palin.

In a television interview yesterday, President Clinton also advised Mr. Biden against going after Ms. Palin directly. Doing so, he said, would likely appeal only to voters already supporting Senator Obama. “I don’t think he has to whack her, or should,” Mr. Clinton said on NBC’s “Meet the Press.” “Everybody that really is upset about Sarah Palin because she’s too conservative or too Alaska or too this, that, or the other thing, they’re already for the Obama-Biden ticket.”

Both parties have already begun the traditional pre-debate efforts to lower expectations for their candidates and raise the bar for their opponents. Mr. Obama’s campaign manager, David Plouffe, told reporters on a conference call Saturday that Ms. Palin was “a terrific debater,” judging from tapes of her performances during campaigns in Alaska.

“She has performed very, very well,” Mr. Plouffe said. “She’s obviously a skilled speaker, so you know we’ll expect that she’ll give a great performance next Thursday.”

Republicans have highlighted Mr. Biden’s frequent gaffes, but have also touted his years in Washington as preparation for the debate. One GOP aide said Mr. Biden has “spent his entire career debating in the Senate and building a reputation as one of the best.”

A close friend and adviser to Mr. McCain, Senator Graham of South Carolina, said criticism of Ms. Palin in the last week had been exaggerated, but he acknowledged that she had work to do on Thursday.

“She’s going to have to show she’s a valuable part of this team, that she’s capable of the job, that she shares John’s philosophy,” he said on “Fox News Sunday.”