By Kristin Jensen and William Roberts

Nov. 7 (Bloomberg) -- Democrats seized an early lead in several pivotal Senate and House races as they battle to overthrow Republican control of Congress in midterm elections shaped by the war in Iraq and corruption scandals.

Democrats picked up Senate seats in Ohio and Pennsylvania and staved off a challenge in New Jersey, according to partial returns and U.S. television network projections. Meanwhile, Democrat Brad Ellsworth defeated Republican Representative John Hostettler in Indiana, a state that reelected President George W. Bush with 60 percent of the vote two years ago.

Democrats need a net gain of 15 seats in the House and six in the Senate to capture both chambers for the first time in 12 years. Dozens of Republican House seats and eight in the Senate are in jeopardy, according to polls and political analysts. All 435 House seats and 33 of the 100 Senate seats are at stake.

The elections are a test of U.S. voters' confidence in Bush, even though he isn't on the ballot. Republicans were counting on their larger campaign war chest and ability to turn out voters to overcome anger over the war and the scandals at home.

``Most midterm congressional elections are about local issues and candidates,'' said Mark Rozell, a public policy professor at George Mason University in Arlington, Virginia. ``But this year, it seems that all politics are national.''

Democratic control of either chamber would open the door to investigations of the Bush administration by new committee chairmen armed with subpoena power and the ability to influence policy on everything from taxes to Iraq.

Early Results

Democrat Bob Casey Jr. defeated Republican Senator Rick Santorum in Pennsylvania. In New Jersey, Democratic Senator Bob Menendez staved off a challenge to his seat, according to network projections. The networks also predicted that Democrat Sherrod Brown unseated Republican Senator Mike DeWine.

Senate races in Maryland, Missouri, Tennessee and Virginia are still too close to call even after polls closed, CNN said. With 68 percent of precincts reporting, Democrat Jim Webb trailed Republican Senator George Allen in Virginia. Allen had 50.5 percent of the vote to Webb's 48.3 percent.

Kentucky Race

In Kentucky, Republican Representative Anne Northup was losing by 1.4 percentage point in her race against Democrat John Yarmuth with 88 percent of the precincts reporting. Analysts consider the Kentucky race to be a bellwether.

At polling places today, about six in 10 voters said they disapproved of the way Bush is handling his job, the Associated Press reported, citing surveys taken by the newswire and television networks. That is roughly the same percentage that opposed the war in Iraq. Respondents were also more inclined to vote for Democratic candidates than Republicans, the AP said.

About three-quarters of voters said scandals mattered to them in deciding how to vote, and they, too, were more likely to side with Democrats, the AP said. CNN reported that voters who considered the economy the most important issue favored Democrats by 20 percentage points.

Historically, incumbency is a powerful weapon that ensures re-election for all but a handful of lawmakers. Analysts note that this easy path back to power is broken roughly every dozen years by a wave of voter dissatisfaction that moves like a brushfire through the dominant party -- and leaves the other virtually unscathed.

Big Waves

The question for Republicans, analysts said before the polls closed, was whether the losses will be as great as the big waves of 1974 and 1994.

``Is the public -- or at least the swing voters -- disgusted with Bush, Republican control, Iraq, the war on terrorism and the perceived general direction of the country?'' said David Schultz, a professor who teaches public policy courses at Hamline University in St. Paul, Minnesota. ``If yes, look for big changes. If not, change will be muted.''

In 1994, when Republicans took control of both chambers, not a single House Republican incumbent lost as Republicans picked up a net 52 seats. In the Senate, Republicans picked up 11 seats, and all incumbents in the party won, while two Democratic incumbents were shown the door.

Experts had predicted only modest Democratic gains until around midyear when Democratic momentum began to build. Republicans were hurt by a scandal over lewd messages that Florida Republican Representative Mark Foley sent to former congressional teenage pages. Foley resigned on Sept. 29.

House Races

Thirty-five House seats, 33 held by Republicans, were regarded as competitive as voters went to the polls. Another 30 seats were at least in play, and 27 of those are held by Republicans.

In the Senate, the four most competitive races were for Republican-controlled seats in Missouri, Montana, Rhode Island and Virginia. Six more seats were also in play, two held by Democrats in Maryland and New Jersey and the other four held by Republicans in Arizona, Ohio, Pennsylvania and Tennessee.

``It will be a moral victory if Republicans hold the Senate, and that's a big question mark,'' said Nathan Gonzales, the political editor for the nonpartisan Rothenberg Political Report in Washington.

As of Oct. 18, the close of the last pre-election reporting period, the three main Republican campaign committees had a cash edge over their Democratic counterparts of more than $17 million, according to Federal Election Commission records.

`72-Hour Plan'

Republicans also deployed their ``72-hour plan'' for turning out supporters, which party leaders have credited for helping nail down victories in 2002 and 2004. White House political adviser Karl Rove and other party strategists have said the expertise they developed in those campaigns could again prove decisive.

Bush and first lady Laura Bush cast their ballots today at about 7 a.m. at the fire station in Crawford, Texas, before heading back to the White House to await the returns.

``Laura and I know it's a privilege to cast our vote,'' the president told reporters. ``Our government is only as good as the willingness of our people to participate in it. Do your duty, cast your ballot and let your voice be heard.''

There were reports of long lines, voting machine malfunctions and court disputes over ballot procedures. In South Carolina, Republican Governor Mark Sanford was turned away at his polling place by election officials who told him he had insufficient identification, CNN reported.

The FBI was investigating reports in Virginia that voters received telephone calls to direct them to the wrong polling place or discourage them from voting.