The seismic event driving the 2010 midterm elections has triggered a tsunami: Republicans have swept to control of the House of Representatives.

That’s the biggest story so far in a turbulent election that followed a volatile and intensely negative political campaign season.

Results so far show a decided shift to the right across the country. But Democrats held ground in some closely watched races and were fighting to keep a Senate majority.

GOP Takes It To The House

A major upheaval was under way in the House of Representatives, where Republicans had picked up at least 37 seats. They need 39 to take control of the House. Results so far suggest that’s likely and that the final total could be considerably higher.

Among those going down was Rep. Rick Boucher of Virginia, who serves on the powerful Judiciary Committee and on Energy and Commerce and has been in office 28 years.

In Indiana, Rep. Baron Hill — a moderate Democrat and fiscal conservative — was ousted by Todd Young, a veteran and lawyer who has been endorsed by Mitt Romney, the former Massachusetts governor and presidential hopeful.

South Carolina elected State Rep. Tim Scott to the House. He will be the first black Republican from the Deep South to serve there since Reconstruction — and also the first black GOP representative since Oklahoma’s J.C. Watts retired in 2003.

Democrats Lose Ground In Senate, Too

It appeared certain that Republicans had picked up four Senate seats previously held by Democrats. Perhaps the biggest news came from Wisconsin, where the GOP’s Ron Johnson knocked off longtime Sen. Russ Feingold.

Also making gains for Republicans were Dan Coats in Indiana, John Boozman (who beat Democratic incumbent Blanche Lincoln in Arkansas) and Gov. John Hoeven, who takes the seat held by retiring Democratic Sen. Byron Dorgan in North Dakota.

Tea Party favorites Rand Paul and Marco Rubio captured Kentucky and Florida, showing the strength of that new political movement. And Roy Blunt won in Missouri, keeping that Senate seat in GOP hands.

But it wasn’t all Republicans all the time. In Delaware, Democrat Chris Coons was able to hold off a challenge from Tea Party candidate Christine O’Donnell.

In West Virginia, Democratic Gov. Joe Manchin claimed the Senate seat vacated by the late Sen. Robert Byrd.

And in Connecticut, longtime Attorney General Richard Blumenthal, a Democrat, was on his way to overcoming a $50 million spending spree by Republican newcomer Linda McMahon.

In Ohio, Republican Rob Portman claimed the seat vacated by fellow Republican George Voinovich. Republican newcomer Kelly Ayotte won in New Hampshire, holding on to another GOP seat. In Kansas, Jerry Moran held down the Senate seat vacated by fellow Republican Sam Brownback.

Democratic incumbents still on the job include Kirsten Gillibrand and Charles Schumer in New York, Pat Leahy in Vermont and Barbara Mikulski in Maryland. Republicans holding on to their seats included Richard Burr in North Carolina, Tom Coburn in Oklahoma, Johnny Isakson in Georgia, Jim DeMint in South Carolina and Richard Shelby in Alabama.

Democrats were trying to defend their hold on both houses of Capitol Hill against an onslaught of candidates from inside and outside the Republican mainstream.

President Obama watched and wondered what the outcome of Tuesday’s vote will mean for his agenda — and his re-election hopes in 2012.

And across the nation, 37 governors’ offices are up for grabs, as well as control of many statehouses. State-by-state outcomes will affect redistricting decisions that could have a lasting impact on the political landscape.