ST PAUL -- Democrats Thursday set about the delicate task of hitting back at Republican vice presidential pick Sarah Palin after she muscled into the political bullring in a combative convention debut.

Barack Obama and other top Democrats were careful to avoid personal attacks on Palin, who was basking in rock star treatment in the US media, trying instead to turn the focus onto her political record and Republican policies.

Democrats who criticized Palin have already been accused of sexism by the McCain camp, and the Obama campaign is familiar with the perils of gender in politics following the bruising primary duel with Hillary Clinton.

"I anticipated this last Thursday in my acceptance speech," Obama said in York, Pennsylvania, when asked if he had been surprised at the vehemence of Palin's broadsides.

"They don't have an agenda to run on. They haven't offered a single concrete idea so far in two nights about how they would make the lives of middle class Americans better.

"They have spent the entire two nights attacking me or extolling John McCain's biography, which is fine, they can use their convention time any way they want.

"But you can't expect that I would be surprised about attacks from Republicans."

Obama also made clear that despite declaring Palin's family and her 17-year-old daughter's pregnancy off limits, he would not hesitate to pick over her record as Alaska governor and a small town mayor.

"The notion that any questions about her work in Alaska is somehow not relevant to her potentially being vice president of the United States doesn't make too much sense to me," Obama said.

"I think she's got a compelling story, but I assume that she wants to be treated the same way that guys want to be treated, which means that their records are under scrutiny.

"I've been through this for 19 months, she's been through it, what, four days so far?"

Obama's vice presidential pick Joseph Biden, who faces a high-stakes showdown with Palin in their running mates debate in October, gave her marks for style not substance.

But, Biden said, she failed to mention "the middle class or health care or about how people are going to fill up their gas tanks.

"I didn't hear a single word about how you're going to get our kids to college," Biden said.

And the Delaware senator, a bruising political player, also opened the expectations game ahead of their meeting in St. Louis, Missouri on October 8.

"Boy, she's going to be a tough debater, she's going to be a skillful debater," Biden told CNN. "She was good."

Another Democrat, Rahm Emanuel, a congressman and former Clinton administration senior aide is a renowned political streetfighter, but also appeared to be reining himself in.

"As someone who has worked on a convention speech or two in my time, I congratulate Sarah Palin for successfully completing the task that John McCain handed her: deliver a speech long on insults and short on ideas," he said in a statement.

"Governor Palin's silence on the economy in her speech only confirmed what so many families already knew: a McCain-Palin administration will give us more of the same Bush-Cheney economics."

Palin used her primetime speech at the Republican National Convention here on Wednesday to hammer Obama, portraying him as a talented wordsmith with little substance, and no record of sacrificing for the American people.

"For a season, a gifted speaker can inspire with his words, for a lifetime, John McCain has inspired with his deeds," she said.