Sept. 10 (Bloomberg) -- Democrats are beginning to worry about losing the presidential election.

After months of leading in voter enthusiasm, fundraising and most surveys, Barack Obama lost momentum to John McCain after the Republican convention last week. McCain has gotten a boost from his pick of Alaska Governor Sarah Palin as his running mate and has surged ahead of Obama in some national polls, while running even in others.

Arizona Senator McCain, 72, is drawing larger crowds to his rallies than ever before. Illinois Senator Obama's campaign, meanwhile, may struggle to keep up the record fundraising pace it has maintained all year.

The campaign's ``novelty has worn off,'' said Representative Bill Pascrell, a New Jersey Democrat. The Obama campaign ``seems to have lost its speed, its response time.''

Republicans used their St. Paul, Minnesota, convention to focus attention on McCain's personal character and leadership qualities, and highlight his independence from President George W. Bush. The message was reinforced by the selection of Palin, who was presented as a reformer who fought oil companies and took on her party in Alaska.

`Best Week'

This has allowed the Republicans to have ``their best week in four years,'' said Representative Artur Davis, an Alabama Democrat. ``McCain is the one Republican who could have been competitive this year because John McCain does his own brand independent of George Bush.''

With Palin, 44, joining him on the stump, McCain came out of his party's convention ``with an energized base,'' said House Democratic Caucus Chairman Rahm Emanuel of Illinois.

In recent days, McCain and Palin have appeared before crowds ranging from 3,000 to 10,000 or more. Yesterday, about 6,000 turned out to see the Republican ticket in Lebanon, Ohio. Prior to the convention, McCain typically appeared at town-hall meetings -- his preferred venue for campaigning -- of about 300 attendees.

McCain's choice of Palin ``allowed the McCain campaign to change the narrative away from McCain being an extension of Bush,'' said Democratic strategist Jenny Backus.

The McCain campaign said donations have been pouring in since the convention, allowing the Republican to narrow, if not eliminate, Obama's longstanding financial advantage. This week, a fundraiser in Chicago, Obama's hometown, yielded $5 million.

Economy, Health Care

Democrats said Obama can respond by capitalizing on his significant lead on issues, particularly the economy and health care, including among many independents who have become the chief target of both campaigns now that the candidates have locked in their parties' nominations.

McCain ``planted his flag strictly off of biography,'' said Bill Buck, a Democratic strategist who has worked on several presidential campaigns. Obama and Democratic vice presidential candidate Joe Biden ``are going to have to be very on-message and push the debate back to the economy.''

Obama, 47, has already adopted a more aggressive tone, going after McCain and Palin and characterizing them as allies of the Bush administration status quo.

The candidate mentioned McCain by name 19 times during a 24-minute speech in Flint, Michigan, on Sept. 8. He focused on the economy and education, areas where he said the Republicans offer nothing new.

Palin and McCain, he said, are trying to ``repackage'' themselves as agents of change.

`Reinvent Yourself'

``I mean you can't just make stuff up,'' he told a crowd of 325. ``You can't just reinvent yourself. The American people aren't stupid.''

The campaign also released a new ad this week saying Palin and McCain are ``anything but'' the mavericks they claim to be, and is portraying McCain's surge in the polls as a short-term blip.

``After our convention, we had a bump; after theirs, they get a bump,'' Obama said in Ohio yesterday. ``What we're going to have to do is to see how things settle out over the next few weeks when people start examining who's actually going to deliver on the issues that people care about.''

Still, Obama campaign manager David Plouffe acknowledged McCain's gains may be more lasting.

``The Republican brand has improved a little bit,'' Plouffe said Sept. 8. ``This is going to be a close race. John McCain had some strength with independent voters that some of their other nominees wouldn't have had.''

Thomas Rick, an independent voter from Valparaiso, Indiana, demonstrates why Obama's advantage has been evaporating.

`Ordinary People'

Rick, a 64-year-old prison chaplain, had been concerned about McCain's closeness to Bush before the Republican convention. He said the candidate's Sept. 4 speech convinced him McCain has integrity and Palin ``identifies with ordinary citizens.''

Democrats said a series of economic reports expected in the coming weeks would help Obama refocus the public's attention away from McCain and Palin and their personal biographies and back to the struggling economy.

``Their strategy was fine for a convention period,'' Buck said. ``The problem for them is that we're moving into the debate phase and I believe that the Republicans have left themselves with a strategic weakness.''

Senator Max Baucus, a Montana Democrat, said his party could regain the advantage as quickly as the Republicans had.

``In politics, a week is a long time,'' Baucus said. ``A lot can happen.''

To contact the reporters on this story: Heidi Przybyla in Washington at hprzybyla@bloomberg.net

Last Updated: September 10, 2008 00:01 EDT