Tea Party Senate candidate Christine O’Donnell defeated establishment Republican Rep. Mike Castle in the Delaware primary election Sept. 14, jeopardizing GOP chances of taking over the Senate.

The right-wing Tea Party Express spent more than $300,000 on TV ads demonizing Castle, who had the party’s backing.

The party’s National Senatorial Campaign Committee had recruited Castle for the race, expecting that the moderate Republican’s long history in the state would make him a sure bet to take the seat held by Democrat Joe Biden until he became Vice President.

Even the most optimistic projections made by the party thus far suggest a Republican takeover of the Senate is impossible without Delaware. The GOP needs 10 seats to win control of that chamber.

Castle’s defeat in the Delaware primary is the eighth time now that a Republican establishment candidate has gone down to defeat because of a growing split in the GOP. Ultra right-wing extremists, making use of a variety of issues but especially an appeal to racism, have turned out enough followers to capture Republican nominations to major offices in various states.

In order to broaden their appeal beyond adherents of the extremist social doctrines they preach, the tea party candidates have often tried to capitalize on certain issues that anger the majority of working people – the bailout of Wall Street corporations and banks with taxpayer funds, being the best example.

They added this issue to their usual campaign to “take back America [from an African American president]” in the Delaware race, in Utah (where they defeated Sen. Robert Bennett), in Texas, where they went after Sen. Kay Bailey Hutchinson for both lack of ideological purity and for having voted for TARP, and in Alaska, where they defeated Sen. Lisa Murkowski, who they linked to both liberal social doctrine and Wall Street banks.

There are no other issues that polls show are important to working people, however, that tea party candidates have supported. They have not backed any jobs programs and have opposed government aid to the unemployed.

While they often rail against “taxes” in general they have not supported the president’s plans which would extend tax cuts for 97 percent of the population.

Fear of the tea party probably helped motivate decisions by Republican Sens. George Voinovich in Ohio and Judd Gregg in New Hampshire not to seek reelection this year.

Just one Republican Senator the group opposed, John McCain of Arizona, has survived a tea party challenge this year. McCain did this by moving even further to the fringe right-wing positions.

The first sign of all of this began back in the spring when, fearing extreme right-wing opposition, Republican Sen. Arlen Specter defected from the GOP to the Democratic Party. Soon after that Charlie Crist, the GOP governor of Florida, quit his Senate GOP primary for the same reason, choosing, instead, to run as an independent.

Tea party leaders like to explain their victories as a sign that people are rising up all over the country against a government controlled by “liberals,” “socialists,” and even “traitors” to so called “American values.”

Most of their victories, however, have been in states where the population is very small and it is easier to win elections or in larger states where the GOP is small, compared to Democratic registration.

Somewhat less obvious than all of this is that major corporate interests have been behind several of the tea party’s most important victories.

Big energy companies with an interest in refuting global warming, for example, have, focused on tea party efforts in Kentucky, Alaska and Delaware.

The tea party candidates in each of those states, now the official Republican senatorial candidates, firmly oppose a cap on carbon emissions.

In Kentucky, big coal mining companies such as Massey Energy, responsible for the deaths of workers in their poorly-regulated mines, help bankroll Rand Paul. (national august 2010 rand paul)

Castle in Delaware was one of eight Republicans who actually voted for the House carbon cap bill. His “cap-and-trade” vote wasn’t the only thing that bothered conservatives but it was an issue that Christine O’Donnell hammered away at constantly.

In Alaska, the energy companies were angry with Lisa Murkowski despite the fact that she was a reliable vote against President Obama on a wide variety of other issues. Her sin was that she acknowledged global warming was real and she met with President Obama to discuss compromises on a cap-and-trade bill. She had voted for cap-and-trade in the past.

Joe Miller made her “liberal climate record” a major issue in his race against her.

History or tradition explains some of what is at work here. Traditionally, when a party loses the presidency, opponents of the party’s leadership tend to do well in the internal party fights over the next few years.

The right-wing purge going on in the GOP, however, is mercilessly claiming many long-time Republican leaders as its victims.

In New York this week, Rick Lazio, a virtual fixture in state Republican politics, also lost his bid for the gubernatorial nomination to tea party-backed Carl Paladino.

In New Hampshire, a Republican senator who voted for the nomination of Sonia Sottomayor to the Supreme Court almost lost to a tea party primary opponent.

Rand Paul, the tea party victor in the Kentucky GOP Senate primary, defeated Trey Grayson, a long-time GOP leader in Kentucky who was the hand-picked candidate of Senate Minority Leader Mitch McConnell.

In Nevada, Sharron Angle won the GOP primary to challenge Democratic Majority Leader Harry Reid.

The quick endorsement of O’Connell today by Mitt Romney’s Free and Strong America PAC is likely the first of numerous indicators that the tumult in the Republican Party will push the entire 2012 GOP presidential field to the right.

The results of all these primaries show that the Republican Party of today is a party led by the likes of Sarah Palin, Jim DeMint (GOP senator from South Carolina), Glenn Beck, Sean Hannity and Rush Limbaugh. DeMint is a leader who has escaped the eye of many of the political pundits but may end up being the leader who should be watched most closely. He is the unofficial leader of the Republican Senate’s tea party caucus, which he hopes to expand.

On the flip side, Democrats, the labor movement and its allies, and progressives generally are encouraged that some of the victories by the right-wing extremists in the Republican Party put back in play races they might have lost before.

Polls going into the Delaware primary show O’Connell, in the general election, trailing her Democratic opponent, Chris Coons by double-digit figures.

In Alaska, the Democrats had no chance to defeat Lisa Murkowski. They have a much better chance against Joe Miller.

Murkowski, herself, is still mulling a write-in-bid. “The Alaska Republican Party,” she said yesterday, “has been hijacked by the Tea Party Express, an outside extremist group.”

In Nevada, polls show Reid on his way to holding onto a Senate seat he was in danger of losing before the tea party’s Angle won the Republican primary.

In New York, polls show Paladino, the tea party candidate, way behind Andrew Cuomo, the Democratic nominee for the governorship.

Despite the good signs, however, progressives cannot become complacent. If, after the defeat of Castle in Delaware, the Republicans are to have any chance of taking over the Senate they will have to work harder and funnel more resources into other Senate races. Carly Fiorina in California, Linda McMahon in Connecticut and Mark Kirk in Illinois become more important than ever to them. Labor and progressive forces in those and other states can expect that they will have to fight harder than ever.