WASHINGTON - As the presidential candidates prepare for the traditional post-Labor Day campaign push, both sides are grappling with the arithmetic of the electoral map.
The campaign, which is emerging as one of the few close races for the presidency in the last century, will be issues-heavy, with Vice President Al Gore and Governor George W. Bush of Texas sparring on education, health care, and the environment.
But the target audience for that debate will be much narrower starting this week, as the two campaigns focus their energies on the handful of states that will tip the electoral college scales in favor of Democrat Gore or Republican Bush.
The fight, Democratic and Republican analysts agree, is for the American center: the middle of the country, the middle class, and the middle of the political spectrum.
''The key states are really in the industrial Midwest,'' said a Republican pollster, Ed Goeas.
''It's going to be a close election, that we know,'' said Stephen Hess, a political analyst with the Brookings Institution, and neither candidate can win without showing well in the nation's heartland. ''There's no hidden load of electoral votes.''
So while Bush and Gore trade barbs on the issues, debate about having debates, and raise money for the last grueling nine weeks of the campaign, their staff members are huddled in offices, looking at maps, doing the math, and figuring out who has which state.
On this topic, at least, the two campaigns are in some agreement. And while the campaigns are fond of insisting that they aren't taking a single vote for granted, now is the time when the two sides make cold, calculating decisions about which states are worthy of a fight to the finish.
For voters in Massachusetts, there won't be many chances to see either candidate for the rest of the campaign season, since both camps have chalked up the Bay State for Gore. The same goes for the overwhelmingly Democratic District of Columbia, which usually does not see Republican candidates at all, unless they end up in the White House.
Bush's home state of Texas is considered a lock for the Republican governor, as are most of the Southern and the Rocky Mountain states. All told, 155 electoral votes appear to be safely in Bush's column. Gore, meanwhile, appears to have a firm grip on 142 electoral votes, including those from delegate-rich California and New York.
It all comes down to the magic number of 270, the number of electoral votes needed to win the presidency. As the national polls have tightened, so have many of the polls in individual states, meaning Bush and Gore are likely to engage in a hard, perhaps bitter, battle that could be decided by just a few electoral votes.
Both campaigns appear upbeat and ready for the traditionally hectic pace of post-Labor Day campaigning. Gore is glowing amid polls showing him neck-and-neck with, or even ahead of, Bush for the first time in months. Bush, despite his slippage, has come back fighting. Last week, the Republicans unleashed a TV ad attacking Gore's credibility.
The conventional wisdom this year is to ignore conventional wisdom. ''There's a lot of misunderstanding about the state of the race, forged by old attitudes toward the states,'' said a Gore strategist, Tad Devine.
For example, the candidate who leads in the polls on Labor Day historically has ended up winning the election. But because only four of the last 25 presidential elections have ended up close, this year's contest may not follow that pattern, Hess said.
Nor can either candidate count on historical precedence in lining up states. Gore, for example, is doing poorly in the South, where President Clinton did well in both 1992 and 1996.
New Hampshire, typically a Republican state (although Clinton won it in 1996), is a dead heat. Meanwhile, Gore cannot count on taking his home state of Tennessee, where, despite his local celebrity, the vice president is ahead by just 5 points.
The impact of the disaffected, reform-minded voter could also tip the electoral scales. In Minnesota, usually a safe Democratic bet, the allegiance of the voters who elected Governor Jesse Ventura, the former professional wrestler and Reform Party member, is up for grabs. Minnesota is considered a battleground state, and a crucial one, with 10 electoral votes.
In Washington state and Oregon, offering a combined 18 electoral votes, the candidacy of the Green Party candidate Ralph Nader could frustrate Gore's campaign. Nader is polling at 4 percent or 5 percent in those states, a seemingly paltry share that nevertheless could put Bush over the top in the Pacific Northwest.
Nader, speaking on NBC's ''Today'' show recently, said he wasn't concerned about taking votes away from Gore. But ''obviously, I am worried about Al Gore taking votes away from me,'' Nader said. ''We all have to earn our votes.''
Gore never mentions Nader in his speeches, and his campaign aides insist that most Nader supporters will pull the lever for Gore, if only as an anti-Bush vote.
But the Democratic vice presidential candidate, Joseph I. Lieberman, appealed to voters last week not to back the longtime consumer advocate. ''A vote for Nader is a vote for Bush,'' Lieberman said at a fund-raiser Friday in Portland, Maine.
Both Bush and Gore are likely to spend most of their time before Election Day in the Midwest, where there are 100 electoral votes in a block of seven states: Ohio, Michigan, Wisconsin, Missouri, Iowa, Illinois, and Minnesota, as well as Pennsylvania, which has 23 electoral votes.
''I'm going to campaign hard in the state of Ohio,'' Bush said on a recent visit there. ''I've got a good chance of winning, but I know I've got to come back and ask for the vote. ... We're going to cover this state with a lot of visits.''
The Gore campaign, meanwhile, is planning to send the vice president up and down the Missisippi and Ohio rivers.
Gore has been making a populist appeal, demonizing health insurance companies, health maintenance organizations, drug companies, and oil companies as he seeks the votes of people who have not benefited as much from the nation's economic boom.
Tailoring his message to this conservative region, Gore rarely mentions issues such as gay rights or abortion rights, instead focusing his message on raising the minimum wage, protecting the rights of workers to strike, and paying for prescription drugs for the elderly.
Bush has swung back, telling Midwestern, middle-class voters that Gore's targeted tax cuts will miss some families, unlike Bush's across-the-board tax cuts.
''Here are middle-income Americans,'' Bush said Friday in Swanton, Ohio, as he stood beside Tami Shelton and her husband, Tim, a truck driver for Wonder Bread. ''They get no tax relief under [Gore's] plan, and under my plan, they get over $2,000 in savings. These are real folks who will end up with real savings.''
The big surprise may come from the South, where the Bush campaign is facing the possibility that Florida, the nation's fourth-most-populous state and once considered a virtual certainty for Bush, could be in play.
While Clinton took Florida in 1996, it is still a conservative, traditionally Republican state, and Bush - whose brother Jeb is governor there - had been seen by both campaigns as the likely winner of Florida's 25 electoral votes.
But Gore appears to be gaining in Florida, with one recent poll showing him ahead by eight points. Even the Gore campaign says that lead is inflated, but that Florida is definitely winnable for the vice president.
''We're starting to get the taste in our mouth now'' that Florida could go Democratic, said a Gore campaign strategist. ''Our issues are strong there,'' with Gore campaigning heavily on long-term care for the elderly, and Medicare coverage of prescription drugs, the aide said.
Buoyed by the recent polls, the Gore campaign is planning an all-out fight for Florida, a Gore aide said. Even if Gore does not end up taking the state, the aide said, the closeness of the race will force Bush to spend more time and money there than he planned, diverting resources from other critical contests.
Still, it is a tough, diverse constituency in Florida. Gore is popular among Democrats in Dade County and in ''condo heaven,'' populated by retirees from New York, New Jersey, and Massachusetts. But he faces trouble from the Cuban-Americans in Miami, who are angry with the Clinton-Gore administration over its handling of the Elian Gonzalez case, and from conservatives in Central Florida and the panhandle, who oppose stricter gun controls and typically are Republican.
''Bush has a much better organization on the ground,'' said James P. Monroe, a professor of political science at the University of Miami. While Gore is leading in at least one Florida poll now, Monroe said, ''on election day, I just don't think that's going to be the case.''
Glen Johnson, with Bush, and Anne E. Kornblut, with Gore, both of the Globe Staff, contributed to this report.
