The biggest challenge may be managing information overload, given the many races and places where Democrats are in trouble.
Five states have polls that close at 7 p.m. EDT, and 16 more close by 8 p.m., featuring plenty of telling races in the East and Midwest. First up: Indiana, Kentucky, South Carolina, Georgia and Vermont, offering the first hard evidence of just how big a night it's going to be for Republicans.
If the GOP can unseat Democratic Rep. Baron Hill in Indiana's hard-fought 9th congressional district, for example, that's a good sign for Republicans trying to take control of the House. And if Republicans can capture all three seats they've got an eye on in Indiana, that could signal a GOP tsunami.
On the other hand, if Democrats hold their ground in Indiana and if their Kentucky Senate candidate, Jack Conway, can beat back Republican Rand Paul, it could be an early indication that GOP gains won't be massive and that the tea party is serving weak brew.
A few tips on what to watch as the returns roll in on Tuesday night: (all times are EDT):Expectations have soared that Republicans will pick up the 40 seats they need to retake control of the House. It can't be done without a strong start across the Midwest.
In Ohio, where polls close at 7:30 p.m., six Democratic-held seats are in jeopardy. In Pennsylvania and Illinois, where polls close at 8 p.m., 10 more are at risk.
If Midwestern incumbents such as Reps. Joe Donnelly in Indiana and John Boccieri in Ohio fall, Republicans are likely headed for huge gains. Measure Democratic resilience if the party holds on to a pair of imperiled Georgia seats, and if Rep. John Spratt can win a new term in South Carolina.
Worth watching in Florida (8 p.m. poll close): a rematch between Democratic Rep. Ron Klein and Republican Allen West. A loser two years ago, West now rides anti-incumbent sentiment and is easily outspending his opponent.
Even if Republicans demonstrate early strength Tuesday night, it will take time for them to lock in enough districts to ensure a GOP majority because the West Coast states of California, Washington and Oregon are home to 67 House districts. In 2006, it was 1 a.m. before it became clear that control of the House had passed from Republicans to Democrats.It would take a true blowout for Republicans to pick up the 10 Senate seats they need for control. The first should be an easy one, in Indiana. But if Paul can't keep Kentucky in the GOP column, it would be a sign of strength for Democrats and a setback for the tea party.
Republicans should have an easy time holding onto one of their own vacant seats in Ohio, where former Republican congressman Rob Portman is favored. But keep an eye on West Virginia, another 7:30 poll-close state, where Democratic Gov. Joe Manchin and Republican millionaire industrialist John Raese are tussling over the seat long held by the late Democrat Robert Byrd. A Republican victory there could keep alive hopes of a GOP majority.
Three-term Sen. Blanche Lincoln could be the first Senate Democratic incumbent to fall, when polls close in Arkansas at 8:30 p.m.
Then there is a series of hard-fought races in the East and Midwest before polls close at 10 p.m. in the most closely watched race: Republicans are out to defeat Senate Majority Leader Harry Reid in Nevada, running against tea party favorite Sharron Angle.
Even if Republicans show huge strength, the nation still could go to sleep with unanswered questions about the Senate: Polls don't close until 1 a.m. in Alaska, where it could take days or weeks to determine the winner of a three-way race for Republican Sen. Lisa Murkowski's seat.
How long could the suspense drag on? In 2006, it took until 8:30 p.m. the day after the election to determine that Democrats had taken control of the Senate from Republicans. And in 2008, it was nearly eight months before it was determined that Democrat Al Franken had won Minnesota's Senate race, giving Democrats their 60th seat in the Senate.South Carolina will offer an early measure Tuesday night of tea party strength: Republican Nikki Haley trailed for months before Sarah Palin's endorsement and a tea party surge helped her nail the GOP nomination. Now she's favored over Democratic state Sen. Vincent Sheehen.
Over the next few hours, results will roll in for the Northeast, where Democrats face tough GOP challenges in Massachusetts, New Hampshire, Vermont, Maine and Connecticut. If Democratic Gov. Deval Patrick goes down in liberal Massachusetts, it's a sign the tea party fury over taxes and big government is spreading far and wide.
There's plenty of suspense in Florida, with an 8 p.m. poll close, in the battle between Republican businessman Rick Scott and Democrat Alex Sink, the state's chief financial officer.
Close contests are expected in Oregon and Hawaii. And polls don't close until 11 p.m. in California, where billionaire businesswoman Meg Whitman and former Gov. Jerry Brown are vying to replace outgoing Republican Gov. Arnold Schwarzenegger.There will be plenty of 2012 tea-leaf-reading Tuesday night, especially when Western results start flowing in.
Sarah Palin has endorsed numerous Republicans, and if they have a good night, so will she.
As for President Obama at midterm, his grade will rely largely on the outcome of the fight for control of Congress. But his re-election campaign also will be affected by the result of gubernatorial races in states like Ohio, Iowa, Florida and his home state of Illinois.