WASHINGTON (AP) _ Democratic former Virginia Gov. Mark Warner breezed to victory in his bid for the Senate on Tuesday, snagging a southern seat long held by Republicans and fueling expectations that Democrats would solidify their now-thin leadership grip over the chamber.

Democratic vice presidential candidate Joe Biden won another six-year term representing Delaware in the Senate, although it would become a moot point if the Democratic ticket wins the presidency.

Warner beat another former governor, Republican Jim Gilmore, in the race to replace retiring five-term Sen. John W. Warner. The two Warners are not related.

Democrats, piggybacking on aggressive Barack Obama voter-registration and get-out-the-vote drives in battleground states, were reaching for a coveted 60-seat, filibuster-proof Senate majority. However, leaders in both parties said reaching that goal is a long shot.

Voters flocked to the polls to fill 35 Senate seats in a year in which both parties said they expected Democratic gains.

With races called in nine states, Democrats claimed victory in six, Republicans in three.

In North Carolina, GOP Sen. Elizabeth Dole was struggling to hold her seat against Democratic state Sen. Kay Hagan. However, Senate Republican leader Mitch McConnell took an early lead in Kentucky against two-time Democratic gubernatorial candidate Bruce Lunsford.

In South Carolina, Republican Sen. Lindsey Graham, a close adviser to GOP presidential nominee Sen. John McCain, won a second term, defeating Democrat Bob Conley. Other Republican winners included Sens. Susan Collins of Maine, a seat Democrats had once eyed as competitive, and Lamar Alexander of Tennessee.

Democratic Sen. John Kerry, the 2004 Democratic presidential nominee, won a fifth term; as did Jay Rockefeller of West Virginia. Democrats Frank Lautenberg of New Jersey and Dick Durbin of Illinois also won new terms.

With Warner’s victory in Virginia, Democrats now control both Senate seats and the governor’s mansion. Virginia usually votes Republican in presidential elections, but this year Democrats viewed it as one of their most promising pick ups.

Yet even bringing their numbers to close to 60 would enable Democrats to exercise far more control than they have now, since some Republicans probably would join them in efforts to break Senate logjams on many bills and judicial appointments.

Senate Democrats now have a tenuous 51-49 majority, and only thanks to the support of two independents. But a slumping economy, an unpopular war and voter fatigue after eight years of President Bush could help them bolster that majority, building on the six seats they added in 2006.

That fueled Democrats’ optimism that the only two Democratic senators would lose their Senate seats as a result of the national elections: Biden and Barack Obama.

And if the Democratic presidential ticket prevails, Democratic governors in Illinois and Delaware are sure to appoint Democrats to replace them.

Biden is running for re-election as senator from Delaware as well as for vice president. The Senate seats of Obama and GOP presidential candidate John McCain are not on the ballot.

Polls were open nationwide with long lines in many places.

Democrats had fewer seats to defend than Republicans. Of the 35 races on Tuesday’s ballot, 23 are now held by Republicans, 12 by Democrats.

In addition to the Virginia seat won by Warner, Democrats also counted as good prospects the seats of two other retiring GOP senators — in Colorado and New Mexico.

In Colorado, Democratic Rep. Mark Udall, son of the late Arizona Rep. Morris “Mo” Udall, faced former Republican Rep. Bob Schaffer for the seat now held by Republican Wayne Allard. And in New Mexico, Democratic Rep. Tom Udall — a cousin of the Colorado Udall — faced Republican Rep. Steve Pearce to succeed retiring Sen. Pete Domenici.

Both Udalls were comfortably ahead in pre-election polls.

Republicans seeking re-election faced tight contests in five other states — Dole in North Carolina, Ted Stevens in Alaska, Norm Coleman in Minnesota, John Sununu in New Hampshire and Gordon Smith in Oregon.

One route to 60 for Democrats was to win these five states on top of Virginia, Colorado and New Mexico, plus pick up at least one of three other closely contested races in Georgia, Kentucky and Mississippi. And not lose any Democratic seats.

Going into the election, only one incumbent Democrat appeared vulnerable: Sen. Mary Landrieu of Louisiana. Republicans made a spirited run at her, but Democrats saw her seat as a safe one.

In one of the most closely watched races, Alaska’s Stevens, at 84, the longest serving Republican in Senate history, sought re-election despite calls from GOP leaders to resign after he was convicted last week of seven counts of lying on Senate financial disclosure forms. He was locked in a tight contest with Democrat Mark Begich, the mayor of Anchorage.

Another closely contested race was in Minnesota, where Republican incumbent Coleman was challenged by Democrat Al Franken, the former “Saturday Night Live” writer and actor. A significant third-party candidate, Independent Dean Barkley, was complicating the race.

Underscoring the closeness of the race, Coleman embarked on an all-night bus tour with overnight stops in St. Cloud, Brainerd, North Branch, and Forest Lake before voting at 9 a.m. CST at the Linwood Recreation Center in St. Paul.

Democrats also took sharp aim at Senate Minority Leader Mitch McConnell, challenged by Democratic businessman Bruce Lunsford in a close and costly race in Kentucky. In North Carolina, a southern state into which the Obama poured heavy resources, Dole, the incumbent, was battling an aggressive challenge by Democratic newcomer Kay Hagan.

Sen. John Ensign, R-Nev., head of the GOP’s senatorial campaign committee, acknowledged ahead of the voting that “Democrats are poised to pick up some seats.” His Democratic counterpart, Sen. Charles Schumer, D-N.Y., predicted “a whole lot of seats” for Democrats, but said reaching a 60-vote majority was unlikely.