( dpa )- Hillary Clinton was hoping for a much needed win in the Democratic presidential nomination battle as Wisconsin held its primary election Tuesday.
Barack Obama has won eight straight contests over his rival since more than 20 states voted on Super Tuesday in early February. Obama held a slim lead over Clinton in Wisconsin opinion polls and was expected to do well in Tuesday's other contest, a caucus in his birth place of Hawaii.
The two candidates have spent the last week shuffling back and forth between Wisconsin and upcoming contests in Ohio and Texas in early March, both of which are considered must wins by the Clinton camp.
Candidates were also kept away from Wisconsin by heavy snowstorms on Sunday that was still expected to depress voter turnout on Tuesday.
Obama has opened up a lead of nearly 70 delegates over Clinton in the overall battle to win the 2,048 needed to capture the Democratic nomination. At stake on Tuesday are 94 pledged delegates and 27 so- called super delegates, which can vote however they wish at the Democrats' nominating convention in August, regardless of the primary outcome.
On the Republican side, John McCain holds a near unassailable lead in delegates over his only remaining rival, Mike Huckabee.
McCain picked up the endorsement of former president George HW Bush on Monday and has focussed his efforts in past weeks on uniting a fractured party ahead of general elections on November 4.
Also Tuesday, showcasing the complicated nature of the US electoral contest, Washington state was due to hold a primary despite already holding a caucus earlier this month. About half of the delegates to the Republican Party's September convention are still up for grabs in the state, while all Democratic delegates were divided up according to the caucus result February 9.