Democratic primary voters in West Virginia showed 28-year congressional veteran Rep. Alan Mollohan, D-W.Va., the door on Tuesday night. 

It came after delegates to the Utah Republican convention ousted Sen. Robert Bennett, R-Utah, from serving a fourth term in Washington over the weekend. 

But the Mollohan loss could signal trouble for Democrats. 

Democratic state Sen. Mike Oliverio toppled Mollohan. Oliverio’s victory made Mollohan the first House casualty in what has already been a turbulent midterm election year. 

Mollohan is only the second House incumbent to lose in two election cycles. Former Rep. Chris Cannon, R-Utah, lost his primary in 2008.

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Oliverio went after Mollohan’s alleged ethical lapses. And pro-life Democrats criticized Mollohan for voting in favor of the health care reform bill. 

In a statement,  Democratic Congressional Campaign Committee Chairman Chris Van Hollen, D-Md., applauded Mollohan for his service in Congress. 

"For more than 25 years, Representative Alan Mollohan has been fighting to preserve West Virginia jobs, strengthen the economy and improve quality of life for the families he represents," Van Hollen said. "Congratulations to Mike Oliverio on his victory tonight.  This was a tough and spirited primary process.  We are confident that West Virginia families will continue to have Democratic representation in this traditionally Democratic seat." 

But Van Hollen faces a challenge. In 1994, one of the reasons Republicans won the House is because they not only vanquished weak members and lawmakers from marginal districts, but wiped out big fish, too. That year, the GOP defeated House Speaker Tom Foley, D-Wash., Ways and Means Committee Chairman Dan Rostenkowski, D-Ill., Judiciary Committee Chairman Jack Brooks, D-Texas, and others. 

Historically, the midterm election is usually a disaster for the party of the president in power. 

Going into this election year, Democrats knew they could potentially lose 25 to 30 seats. That’s consistent with midterm election history. But for the GOP to win the House, they have to knock off senior members. Like Mollohan. 

Mollohan’s defeat is the latest chapter in a trend that started months ago. 

House Science Committee Chairman Bart Gordon, D-Tenn., announced his retirement last year. Another cardinal, Rep. Jack Murtha. D-Pa., died unexpectedly in February. That shifted Murtha's seat into play. 

Last week, House Appropriations Committee Chairman Dave Obey, D-Wis., announced his retirement. Obey faced a tough re-election campaign. 

Now Mollohan has fallen. 

House Minority Leader John Boehner, R-Ohio, said "politicians should beware."

"The American people are awake, they are more involved in their government than any other time in our history, and what irritates the American people most, is the arrogance in Washington," he said. "The majority here is not listening to the people."

The GOP also has House Budget Committee Chairman John Spratt, D-S.C., and Armed Services Committee Chairman Ike Skelton, D-Mo., in their crosshairs. 

If these members lose, that could be the difference between Republicans winning 25 to 30 seats or reclaiming control of the House. 

On the campaign trail, Democratic nominee Mike Oliverio told voters that if they sent him to Washington he wouldn't vote for Nancy Pelosi as Speaker of the House. 

And if this trend continues, Oliverio might not have to. 

Oliverio now squares off with former West Virginia Republican Party Chairman David McKinley.
Mollohan chaired the House Commerce, Justice and Science Appropriations Subcommittee. 

Appropriations subcommittees are choice assignments. They determine how much federal agencies can spend on specific programs. In fact, Mollohan and the chairs of other appropriations subcommittees are known in Congress as "cardinals." It’s a nod to Rome because of the eminence these lawmakers hold over their swath of federal spending.