Forget soccer moms, security moms and NASCAR dads — the ultimate swing group this year may be the former party stalwarts each campaign is angling to poach from the other party, and chief among those are supporters of Sen. Hillary Rodham Clinton.
On Monday, Sen. John McCain struck first, with Republicans deploying surrogates and running a new commercial featuring a Clinton delegate who was ousted from Democrats’ nominating convention and is now supporting Mr. McCain.
“I am exactly like millions of other Clinton supporters. I do believe people will come out and support Senator McCain,” said Debra Bartoshevich, a Clinton supporter and one-time delegate who was kicked off the convention list earlier this summer after she said Sen. Barack Obama wasn’t qualified to be president.
“I know there are more delegates. I spoke to a lot of delegates who are in the same position I am in, but they are not ready to come out yet,” she said.
Mr. Obama counters this week with speeches from the convention by two Republicans, former Rep. Jim Leach of Iowa and Jim Whitaker, mayor of Fairbanks, Alaska.
Campaigning in Davenport, Iowa, at an event designed to convince independents and Republicans to support him, Mr. Obama was introduced by longtime Republican Randy Wehrman.
“Republicans across the country like myself are just as eager as Democrats an independents to elect a leader with new ideas and a proven ability to work with all sides,” Mr. Wehrman said. “To some here today, at one time that person might have been John McCain, and it might have been for me, too, back in 2000 [when he was] the self-described original maverick. However, I imagine the reason you are sitting here today is because you are wondering, like myself, what happened to the maverick.”
Going after the other party’s voters is standard practice, and both parties like to have prominent crossover figures speak at their conventions.
But this year the competition is more intense. On the one hand, polls show fewer voters identify as Republicans than did four years ago, while on the other side, Mrs. Clinton has shined a spotlight on a group of Democrats uneasy with Mr. Obama as their nominee.
Republicans are trying to exploit that opening, scoring their biggest coup in having Sen. Joe Lieberman of Connecticut, the 2000 Democratic vice-presidential nominee, speak at their convention’s opening night.
They are also bringing four Democrats to Denver on Monday, at least three of them former Clinton supporters, to explain why they are backing Mr. McCain.
“I have been a Democrat for over 30 years. I have been a lifelong Hispanic. Well, Obama has ignored us. He does not even know we are around,” said Silverio Salazar, a former Democratic Party activist in Pueblo, Colo., whose cousins are Sen. Ken Salazar and Rep. John Salazar, both of whom are supporting Mr. Obama.
“I strongly feel it’s our duty and our obligation to get out there and let these Democrats and these Hispanics know, it’s OK, you don’t have to vote Democratic just because your ancestors did.”
Carly Fiorina, a top adviser to Mr. McCain, has been traveling the country to try to build support for the Republican among women, Democrats and independents.
Obama adviser Valerie Jarrett said Monday she is using some of her time in Denver doing counterprogramming with women who had supported Mrs. Clinton, working to convince them to support the Illinois senator.
“They are women who really wanted to hear directly from someone who knew Senator Obama to try to answer their questions and their reservations that they had,” she said during a breakfast sponsored by the Christian Science Monitor.
Mrs. Clinton, in an attempt to dismiss any lingering doubts about where her support lies, said she would release her delegates, freeing them to vote for Mr. Obama.
“We are gathered here in Denver for a very clear and simple purpose, and that is to come out of this convention energized and excited and ready to elect Barack Obama as the next president of the United States,” Mrs. Clinton said at the New York state Democratic delegation breakfast. “And now what I ask each and every one [of my supporters] is to work as hard for Barack and Joe Biden as you worked for me.”
Yet Mrs. Clinton stopped short of telling her backers how to vote, saying that she understands her supporters’ frustrations and realizes some of her delegates won’t heed her request to support Mr. Obama. She said she “doesn’t know” what to do to convince those in her delegation who refuse to support Mr. Obama. “I’m doing everything I can possibly do.”
As the delegates began to filter in to the Pepsi Center on Monday afternoon, the man proudly wearing his Hillary T-shirt was hard to miss. Michael Wagner, a delegate from Washington state, was one of those who fought to ensure Mrs. Clinton’s name would be placed into nomination here.
He said his pro-Clinton stance doesn’t have to mean anti-Obama, but he said he doesn’t think the presumptive Democratic nominee has enough experience.
“I feel that at age 47 you should have some accomplishments to show the work you have been doing,” he said.
A CNN poll released this weekend found that just 66 percent of Democrats who wanted to see Mrs. Clinton as their nominee are backing Mr. Obama, which is down from 75 percent at the end of June. Of the others, 27 percent say they’ll support Mr. McCain, up from 16 percent in June.
Campaigning in Iowa, Mr. Obama said there is ground to make up among some Clinton supporters.
“That’s not surprising,” he said, but he said Mrs. Clinton and her husband can help this week with their own convention speeches.
“I am absolutely convinced that both Hillary Clinton and Bill Clinton understand the stakes. They understand that if we keep on doing the same things that we are doing, which is what John McCain intends, that the American family is going to have a harder time paying the bills,” he said.
• Sean Lengell, Christina Bellantoni, Karen Goldberg Goff and Erin Moffet contributed to this article. S.A. Miller reported from the campaign trail with Mr. Obama.