Updated

President Bush and John Kerry are in a race to see who reaches the magic number of 270 — a majority of the 538 available electoral votes that will guarantee one of them the presidency.

The president and vice president are chosen by the Electoral College, rather than a majority of the popular vote. Each state's electoral college count is based on the number of senators and congressional districts represented in the state. The District of Columbia also has three electoral votes.

The Electoral College usually casts its ballots based on the winner of the popular vote in the state. With many states' popular votes already clearly leaning toward one of the candidates, Bush and Kerry are crisscrossing the nation to campaign in the few states whose voters are undecided and whose electoral votes could make the difference on Election Day.

"These are the states we have to keep an eye on, and they're all too close to call because of this mixture of economic insecurity and terror," said former Ohio congressman John Kasich, host of FOX News' "The Heartland."

The Battle of the Purple

Over the last several weeks, the number of those so-called battleground states — those neither blue for Democrat nor red for Republican, but instead somewhere in between — has narrowed.

According to RealClearPolitics.com, the remaining states available for the taking are Iowa (7 electoral votes), Florida (27), New Mexico (5), Ohio (20), Pennsylvania (21) and Wisconsin (10). Add to that Maine's one electoral vote from the 2nd Congressional District, since Maine, with four electoral votes total, permits its electoral votes to be split. All together, 91 electoral votes are considered up for grabs.

RealClearPolitics.com tallies 176 electoral votes solidly behind Bush from red states while another 51 votes "lean" toward Bush. Kerry has 153 votes from the blue states and another 67 votes from those that lean Kerry, the Web site says with some hesitation.

"It's sort of fluid right now," said John McIntyre, editor of RealClearPolitics.com.

In order to reach the 270-vote threshold, Bush needs to win at least one currently undecided state from the group that went for Al Gore in 2000. For Kerry to win, he needs to grab at least one now-uncommitted state from the column Bush won four years ago.

In 2000, Gore won the battleground states of Oregon, New Mexico, Iowa, Wisconsin, Minnesota, Pennsylvania, New Jersey and Delaware. Bush won Nevada, Colorado, Florida, Ohio and West Virginia.

Now, both camps are focusing on Florida and Ohio. In any election year, these are the two swing states in the country with the highest number of electoral votes. Taken with Pennsylvania, these three states offer up 68 votes.

"Whoever wins two of those three wins the White House," Democratic consultant Greg Haas of Columbus, Ohio, told The Associated Press.

A national Mason-Dixon poll conducted Oct. 14-16 of 625 registered Ohio voters gives the Bush-Cheney ticket 48 percent over the Kerry-Edwards ticket's 45 percent, but still within the margin of error. A FOX News-Opinion Dynamics poll released Wednesday showed Bush ahead of Kerry 49-44 in Ohio. That poll of 800 likely voters was conducted Oct. 17-18 and also fell within the 3.5-point margin.

Wisconsin and Iowa for Bush are "sort of a fallback if he loses Ohio … whereas if Kerry loses Ohio, he's done," McIntyre said.

New Jersey — a state that lost about 700 residents in the Sept. 11, 2001, terror attacks — hasn't backed a Republican presidential candidate since 1988, but polls show the president running surprisingly competitive there.

Bush was in the Garden State on Monday, and in Florida, Ohio and Pennsylvania on Tuesday. He made stops Wednesday in Iowa, Minnesota and Wisconsin, which total 27 electoral votes, or one-tenth the number needed for the presidency. And on Thursday, he was in Pennsylvania again.

Between July 30 and Oct. 20, Bush made eight visits to Iowa, six to Wisconsin, nine to Ohio, two to Oregon, five to Minnesota, nine to Pennsylvania, seven to Florida and three to New Mexico.

Kerry was in Florida, Pennsylvania and Colorado on Monday; Pennsylvania on Tuesday; and Iowa, Ohio and Pennsylvania on Wednesday. Kerry was hunting for geese — and votes — near Youngstown, Ohio, on Thursday before heading to Minnesota.

"Ohio is a huge prize, and all the pictures of Kerry carrying that gun and going hunting is meant to reassure the hunters and gun owners in Pennsylvania, Ohio, and West Virginia, in particular, but also in Minnesota and Wisconsin," said Hal Bruno, retired political director for ABC News.

Bruno said Pennsylvania, high on both candidates' lists of places to visit, is also an unrelenting battleground.

"It was close four years ago. It's a key prize, it's a state that Democrats must win in order to win the election, and it's a state that George Bush has wanted to take away for four years. He's been camping out there ever since he was elected president," Bruno said.

In Pennsylvania, Philadelphia voters likely will vote for Kerry. But the well-populated suburbs around the city are traditionally Republican, though perhaps not the type of Republicans that may go for Bush. Therefore, they are being courted by the Democratic candidate while Bush reaches out to conservative Democrats in other parts of the state, said Dennis Roddy, political columnist for the Pittsburgh Post-Gazette.

"The Democrats tend to be more conservative than Democrats in other states. Our Republicans tend to be more moderate than Republicans in other states. In the ... suburbs around Philadelphia, the four counties there, Republicans have tended to be pro-choice and the president gets killed among Republican pro-choice women in those counties. [The Bush campaign is] working hard to move western Pennsylvania," Roddy said.

Polls elsewhere point to a neck-and-neck race in Iowa, with similar results in Ohio, Minnesota and Florida.

"Florida's a tossup … it could definitely go either way … it's going to come down to the wire … we could, God forbid, see another recount somewhere," said Democratic strategist Doug Hattaway.

Sending the Message Home

The general group of states considered "battlegrounds" this year is, for the most part, nearly identical to those up for grabs in 2000.

"They've shifted a little bit because of who's running — you've got a Northeastern senator versus Al Gore, who was from Tennessee," McIntyre said, noting that in 2000, Gore and Bill Clinton spent time trying to win over Southern states like Tennessee and Arkansas, so "those states were probably more in play."

McIntyre also noted that West Virginia voted Democrat for decades until Gore was defeated there in 2000. "That's almost out of play now for Kerry — that's moved all the way back over to the Republican states," he said.

Iowa and Wisconsin were essentially tied in 2000 and have been moving Republican since then, he said.

"I'm sure the Bush campaign is certainly giving more time to a state like Wisconsin than they did before, the same is true for Minnesota and Iowa because those are states that are more fertile ground for Republicans than they were four years ago," McIntyre said.

"I suspect, because Kerry's a Northeasterner, besides Florida, I think [the Kerry campaign has] just written off the South."

To seal the deal, the candidates have been pounding home messages relevant to the communities they meet.

The White House rivals have focused on issues such as Social Security, Medicare and the current flu-vaccine shortage as they address Florida's huge senior citizen population. They switch gears to discuss milk subsidies in Wisconsin.

In Ohio, a state that had 346,000 unemployed workers in August, both candidates have been focused on their economic messages.

"With the tremendous job loss we have in Ohio, the Democrats have a greater chance there than we've had in many, many years," said Vic Fazio, former California congressman and chairman of the Democratic Congressional Campaign Committee.

"I think in both Pennsylvania and Ohio, more than anything else, it is the economy. I think in West Virginia, it's the economy as well," added Bruno. "But don't forget, when it gets that close, as these states seem to be ... any little thing can help."