A look of the key races in the 50 states:
ALABAMA _ Republican Sen. Richard Shelby cruising to a fifth term in heavily Republican state. Republican Robert Bentley favored in gubernatorial race
ALASKA _ Sen. Lisa Murkowski in unpredictable write-in campaign after losing GOP primary in tea party revolt. Republican Sean Parnell favored for governor
ARIZONA _ Sen. John McCain coasting to fifth term after tough GOP primary. Gov. Jan Brewer also on track toward re-election. Four House Democrats in trouble.
ARKANSAS _ Two-term Democratic Sen. Blanche Lincoln likely loser to Rep. John Boozman. GOP aims to win two open Democratic House seats.
CALIFORNIA _ Former Gov. Jerry Brown leads Republican Meg Whitman in polls. Democratic Sen. Barbara Boxer in close race with Carly Fiorina.
COLORADO _ Sen. Michael Bennet and tea party-backed Republican Ken Buck in close race. Denver Mayor John Hickenlooper favored for governor.
CONNECTICUT _ Competitive governor's race between Democrat Dan Malloy and Republican Tom Foley. Attorney General Richard Blumenthal favored over GOP candidate Linda McMahon for Senate.
DELAWARE _ GOP candidate Christine O'Donnell never got traction in Senate race versus Chris Coons. Rare pickup opportunity for House Democrats.
FLORIDA _ Marco Rubio coasting to Senate win for GOP. Democrat Alex Sink and Republican Rick Scott in fierce governor's race. GOP targets four House seats.
GEORGIA _ Republicans favored for governor (former Rep. Nathan Deal) and especially Senate (Johnny Isakson seeking another term).
HAWAII _ Neil Abercrombie tries to regain governorship for Democrats. GOP Rep. Charles Djou tries to hang on. Eight-term Democratic Sen. Daniel Inouye poised to win another.
IDAHO _ Republican C.L. "Butch" Otter headed for new term as governor. Republican Sen. Mike Crapo cruising to re-election in Senate. Democrat Walt Minnick wins tea party backing in re-election race
ILLINOIS _ Republicans make play for governor, Senate seat and three House seats in Obama's home state. Real race is 2011 Chicago mayoral election.
INDIANA _ Former GOP Sen. Dan Coats on his way back to Senate. Republicans poised to win one House Democratic-held House seat and challenge for two.
IOWA _ Former Gov. Terry Branstad favored to defeat Democratic Gov. Chet Culver. Republican Sen. Charles Grassley coasting to new term.
KANSAS _ Republican Sen. Sam Brownback awaiting election as governor. GOP Rep. Jerry Moran easing into Senate seat.
KENTUCKY _ Tea party favorite Rand Paul builds modest lead in late polls in Senate race. Did Democrat Jack Conway's Aqua Buddha ad backfire?
LOUISIANA _ GOP David Vitter on track to win new Senate term, says wife, family, God and voters forgive him in sex scandal. GOP Rep. Joseph Cao likely loser.
MAINE _ Tea party favorite Paul LePage in competitive four-way governor's race.
MARYLAND _ Gov. Martin O'Malley mild favorite for re-election after stiff challenge ex-Gov. Bob Ehrlich. Sen. Barbara Mikulski on track to win fifth term.
MASSACHUSETTS _ Gov. Deval Patrick tries to fend off GOP challenger in Democratic-leaning state. Rep. Barney Frank pressed in tougher-than-expected campaign
MICHIGAN _ Rick Snyder poised to return governor's office to GOP hands. Three Democratic House seats in play.
MINNESOTA _ Former Democratic Sen. Mark Dayton and Republican Tom Emmer in competitive race for governor.
MISSISSIPPI _ Republicans target Democratic Reps. Travis Childers and Gene Taylor in GOP-leaning state.
MISSOURI _ GOP Rep. Roy Blunt coasting to Senate victory. Veteran Democratic Rep. Ike Skelton battling for new term.
MONTANA _ GOP Rep. Dennis Rehberg coasting to new term in possible tune-up for 2012 Senate race.
NEBRASKA _ GOP Gov. Dave Heineman en route to new term in heavily Republican state.
NEVADA _ Senate Majority Leader Harry Reid in extremely close race with Republican Sharron Angle in state with 14.4 percent joblessness.
NEW HAMPSHIRE _ Democratic Gov. John Lynch favored for fourth term. Republican Kelly Ayotte headed for the Senate in first run for federal office.
NEW JERSEY _ GOP challenging Rep. John Adler in state where Democrats lost governor's office a year ago in early sign of voter anger.
NEW MEXICO_ GOP prosecutor Susana Martinez slight favorite for governor in race against Diane Denish. GOP aims for two Democratic House seats.
NEW YORK _ Democrat Andrew Cuomo comfortably ahead in polls for governor. Chuck Schumer and Kirsten Gillibrand poised to return to Senate from Democratic state.
NORTH CAROLINA _ GOP Sen. Richard Burr cruising to re-election.
NORTH DAKOTA _ Gov. John Hoeven gives GOP a solid shot at Senate pickup in seat held by retiring Democrat. Democratic Rep. Earl Pomeroy in trouble.
OHIO _ Democratic Gov. Ted Strickland and former Rep. John Kasich in tight race; Rob Portman a likely Senate seat win for GOP.
OKLAHOMA _ GOP Rep. Mary Fallin favored for governor while Tom Coburn coasts to re-election to Senate
OREGON _ Democratic Sen. Ron Wyden poised to win re-election. Ex-Democratic Gov. John Kitzhaber and ex-pro basketballer Chris Dudley in close gubernatorial race.
PENNSYLVANIA _ Competitive races for governor and Senate in classic swing state. Republicans eye House pickups.
RHODE ISLAND _ Republican-turned-independent Lincoln Chafee tries for governorship his father once held. Democrat Frank Caprio criticizes Obama.
SOUTH CAROLINA _ Tea party favorite Nikki Haley favored in gubernatorial race. GOP Sen. Jim DeMint coasting to likely win.
SOUTH DAKOTA _ GOP Sen. John Thune cruising to re-election. Prelude to presidential race? Democratic Rep. Stephanie Herseth Sandlin struggling.
TENNESSEE _ Bill Haslem favored for governor in Republican pick-up opportunity. Two Democratic retirements give House GOP big targets.
TEXAS _ GOP Gov. Rick Perry favored over Bill White for new term.
UTAH _ Republican Mike Lee coasting to Senate after tea party jettisoned GOP Sen. Bob Bennett last spring. GOP Gov. Gary Herbert likely winning new term.
VERMONT _ Democratic Sen. Patrick Leahy poised to get six more years in seat he first won in 1974. Competitive race for governor.
VIRGINIA _ Republicans take aim at three Democratic House freshmen. Obama campaigned late for one, Tom Perriello
WASHINGTON _ Three-term Democratic Sen. Patty Murray has struggled in Democratic-leaning state against Republican Dino Rossi.
WEST VIRGINIA _ Gov. Joe Manchin in close race with Republican John Raese to fill out the term of the late Sen. Robert Byrd.
WISCONSIN _ Three-term Democratic Sen. Russell Feingold is the underdog to Republican challenger Ron Johnson. Governor's race competitive.
WYOMING _ Governor's office looks headed back to Republicans with two-term Democrat retiring.