By CQ Staff

Two years after the first exploratory committees were formed and the first money raised, the campaigns for the White House, the Senate and the House are at an end. The winners of the closest contests probably won’t be known before Wednesday — or maybe later, especially if election officials are swamped by an enormous turnout and related snafus and contentiousness at the polls. But odds are that the next president, and the scope of Democratic gains in Congress, will be known by the time polls close on the West Coast at 11 p.m. EST Tuesday, because the voting in several bellwether states will have ended — and “projected winners” in clear-cut races will have been called based on the exit polls — by dinnertime in Washington. A guide to watching the early returns (all times are EST):

6 P.M. Polls close in most of Indiana and about half of Kentucky. If the initial returns make it clear that Indiana will get colored blue on the networks’ maps for the first time since 1964 — even before the polls close, one hour later, in the traditionally Democratic areas near Chicago that remain on Central Standard Time — it will be a clear sign that the national trend is toward Barack Obama . He’s ceded Kentucky to John McCain ; the Senate race is the one to watch there. If Minority Leader Mitch McConnell falls to nursing-home-chain owner Bruce Lunsford, that means Democratic prospects of winning 60 seats go way up. If Republican Anne Northup wins back her Louisville seat in an upset against freshman John Yarmuth , that would signal the GOP is going to stem a House Democratic landslide. The House bellwether in Indiana is lawyer Michael Montagano’s surge against Republican Mark Souder , who’s had the seat since his opponent was 13.

6 p.m.-7:30 p.m.: Timeline: Click Here to View Chart

7 P.M. Polls closing in four Southern states may point the way for the rest of the evening. Obama’s forces are now almost banking on winning Virginia, which has gone Republican the past 10 times. A McCain win could mean he’s built a firewall against Obama’s insurgencies into almost a dozen traditionally “red” states. (It also probably means Rep. Virgil H. Goode Jr. has warded off an upset.) Florida, the legendary battleground of 2000, is once again a presidential tossup; down-ballot, lawyer Alan Grayson and ex-state Rep. Suzanne Kosmas are favored to take away from the GOP House seats in and near Orlando, and the Democrats have serious shots in four more districts farther south. In Georgia, polling suggests that Obama has been rapidly closing McCain’s lead, while Democratic former state Rep. Jim Martin has surged into a Senate tossup with first-term Republican Saxby Chambliss . In South Carolina, upsets of House Republicans Henry E. Brown Jr. and Joe Wilson would foreshadow a big Democratic day.

7:30 P.M. With 20 electoral votes, Ohio is the seventh-biggest presidential prize, and no Republican has ever won the White House without it. So a victory by Obama, who has done consistently better in the state’s polls since the middle of September, might be the strongest sign that he will win the night. (If he scores an upset next door in West Virginia, where he got just one-quarter of the primary vote, the election’s almost certainly decided — and Democratic Senate aide Anne Barth may well have been swept in, denying Republican Shelly Moore Capito a fifth House term.) A McCain upset in Ohio would show that sophisticated and expensive polling can be trusted only so much. And if Republicans can hold both open House seats they’re defending, they probably will do better than expected nationwide. In the Columbus area, it’s GOP state Sen. Steve Stivers vs. Democratic county Commissioner Mary Jo Kilroy, who almost won last time. Two state senators are squared off in the Canton area: Republican Kirk Schuring against Democrat John Boccieri.