Senator John Kerry stumped in Florida Sunday, one day after President George W. Bush turned his Marine One chopper into a campaign prop there. His running mate, Senator John Edwards, was swinging through Ohio.

Bush has a scheduled campaign appearance later Sunday in New Mexico, where his running mate, Vice President Dick Cheney, campaigned on Saturday.

Florida, Ohio and New Mexico are among about 11-12 states where the two candidates are essentially locked in a dead heat in polls after polls. With only 9 days to go, the race remains too close to call, with gaps in various polls well within the margin of error of each poll.

The two candidates are expected to focus relentlessly on those battleground states during the last week of campaigns, laying out plans for a barrage of visits and television advertisements.

Florida, Pennsylvania and Ohio are among the most important battlegrounds with a total of 68 electoral votes, more than half of the uncertain electoral votes. It was widely assumed that any candidate who wins two of three big states will win the presidency.

Bush is battling to hold on to Florida and Ohio, the two states he won in 2000 while Kerry is working to keep a slim lead in Pennsylvania, a state former vice president Al Gore won four years ago.

The contest in Florida, where only 537 votes sent Bush to the White House in last election, became so tight this time that the outcome is almost surely going to be a function of turnout.

That's why Gore went to Florida Sunday in an effort to mobilize African-American voters to make sure they go to the polling stations.

"If anybody ever tells you that one vote doesn't count, you tell them to come talk to me," Gore said at a stop in Jacksonville, where black leaders charged that thousands of votes were discarded four years ago.

Bush won Ohio by a four-percentage-point margin in 2000 and once enjoyed an advantage over Kerry there, but latest polls have showed that it has become a battleground amid growing concern about the economy and jobs.

Kerry has maintained a slim lead in Pennsylvania, but the Bush campaign has worked hard to swing the state. Bush made his 41st visit to Pennsylvania on Friday, one time more than he visited his ranch in Crawford, Texas since he came to office in 2001.

Among other smaller swing states, Bush is struggling to hold on to New Hampshire, a state close to Kerry's home state of Massachusetts. Kerry, meanwhile, is trying not to lose Iowa, Wisconsin and New Mexico.

In the last days of the race, the two sides are expected to struggle for control of the agenda. Bush will repeat his message that he is a more credible commander in an age of terrorism, and Kerry will try to turn the election into a referendum on Bush's record on jobs, health care and Social Security.