“I’m not feeling very positive,” said Awilda Marquez, a prominent Democrat in Colorado. “I know that it’s only the first debate, but he can’t seem to change the relentless negative coverage. Romney has been able to take control.”

Her nervousness was echoed by roughly a dozen Democrats in interviews across the country this week before Obama’s next opportunity to get his campaign back on track — Vice President Joe Biden’s debate Thursday against Republican Paul Ryan…

But there are rumblings in their ranks about whether Obama’s campaign has been aggressive enough coming out of the debate, particularly in accusing Romney of lying about his positions and abandoning the conservative policies he embraced during the GOP primary.

Several strategists said they were perplexed that the campaign, nearing $1 billion in fundraising, wasn’t churning out television advertisements juxtaposing clips of Romney from earlier in the year with his comments during the debate. That’s allowing Romney, they say, to get away with shifting to the center.