WASHINGTON, Aug 9: Senator Joe Lieberman, crippled by his support for the Iraq war and Israel, lost the Democratic nomination for a fourth term to an upstart challenger.

His loss to Ned Lamont in Tuesday’s polls made him only the fourth incumbent senator to lose a primary since 1980. But on Wednesday he filed nominations papers to contest the November ballot as an independent candidate.

The entire House of Representatives and half of the Senate go for re-election in November.

For Mr Lieberman, Democratic nomination was initially considered a routine party affair which many believed would lead to an easy re-election.

But Mr Lamont turned the Democratic Party primary into a referendum on the Iraq war by saying that since Mr Lieberman supported President Bush’s decision to go to war he no longer deserves party nomination.

For weeks, the Connecticut Senate race dominated the political landscape in the US as polls indicated that Democratic voters were so disgusted with President Bush’s pro-war policies that they would reject one of their own key leaders to demonstrate their opposition to the war.

Even a strong endorsement by former President Bill Clinton, who is still considered popular among Democrats, could not save Mr Lieberman.

It was a surprise exit for a politician who in 2004 led the early polls for the Democratic presidential nomination and later came within a few hundred votes from becoming vice-president.

Many political commentators had hoped that Mr Lieberman’s strong support for Democratic causes — such as abortion and social security — would ultimately win the party nomination for him.

They were wrong. His steadfast support for Israel and refusal to condemn President Bush’s Iraq policies played a decisive role and he lost.

Mr Lemont’s victory, by a margin of four points, sends a signal to other Democratic leaders as well that they could be next if they do not re-adjust their positions on the war.

This breaks the previous record for turnout in a state-wide primary, which had been 38.8 per cent in 1970.

The consequences of this historic intra-party fight could go even further.

The defeat of America’s most prominent Jewish politician may alarm the Jewish community that traditionally gives over 80 per cent of its support to the Democratic Party.

Results of the Connecticut primary are also a cause of concern for the ruling Republicans who may lose their control of the US Congress after almost 12 years.