Clinton 'wins key Democrat vote'

Hillary Clinton has beaten Democratic rival Barack Obama in a critical vote in the US state of Pennsylvania, according to early results.
However, it is not yet clear how large her margin of victory will be. Analysts say she needs a big win to keep her campaign alive, but she disputes that.

Hillary Clinton has tried to play down the need to win by a large margin

Mr Obama had predicted he would lose but said he had made big progress in reducing Mrs Clinton's initial lead.
Based on 10% of returns counted, Mrs Clinton led Mr Obama by 55% to 45%.
Preliminary exit polls for the Associated Press and US television networks suggested a high turnout among voters over 60 and that six in 10 voters were women - both groups which have favoured Mrs Clinton.

Hillary Clinton's threat to Iran
About a quarter of those surveyed said they had a postgraduate education and about the same said they had a household income of more than $100,000 last year. Such groups have tended to prefer Mr Obama.
In the final hours of campaigning, Mrs Clinton tried to play down the idea she needed a large margin of victory, saying: "I think a win under any circumstances is a terrific achievement."
And she highlighted Mr Obama's significant edge in terms of spending, asking: "Maybe the question ought to be, why can't he close the deal with his extraordinary financial advantage, why can't he win in a state like this, if that is the way it turns out to be?"
Mrs Clinton earlier emphasised what she says is a strength - her leadership ability and foreign affairs credentials.
As the candidates appeared on the US morning talk show circuit, Mrs Clinton was asked how she would respond if Iran launched a nuclear attack on Israel, and replied with a stark warning.
DEMOCRATIC DELEGATES
Barack Obama:
Pledged delegates: 1,415
Super-delegates: 233
Total: 1,648
Hillary Clinton:
Pledged delegates: 1,251
Super-delegates: 258
Total: 1,509
Source: AP estimates on 22 April
In pictures: Pennsylvania primary
Justin Webb's blog
Wagnerian drama
Pennsylvania voters' views
"If I'm the president, we will attack Iran... we would be able to totally obliterate them," she told TV network ABC.
"That's a terrible thing to say, but those people who run Iran need to understand that, because that perhaps will deter them from doing something that would be reckless, foolish and tragic."
In response, Mr Obama said: "Using words like 'obliterate' - it doesn't actually produce good results, and so I'm not interested in sabre-rattling."
He said only that Iran should know he would respond "forcefully" to an attack on any US ally.
The US fears Iran is trying to acquire nuclear weapons, and could use them against Israel. Iran insists its nuclear programme is solely for power generation.
Last big state
With four million registered Democrats, and 158 pledged delegates to the Democratic Party's nominating convention in August, Pennsylvania is the last of the big states to hold a primary.

Philadelphia residents discuss the Democratic presidential hopefuls

Although Mrs Clinton is behind in the delegate count and in the total votes cast, she has won most of the big state contests.
And the white working class voters who have formed the backbone of her support so far are a significant constituency in the state.
With the delegates split in proportion to the vote, neither candidate is expected to win sufficient pledged delegates to seal the nomination in the remaining primaries, and the two are courting 800 or so unelected "super-delegates".
Pennsylvania provides a key test for Mrs Clinton's argument - which she hopes will sway the super-delegates - that only she will be able to secure wins in critical large states come November's presidential election.
Clinton 'favourite'
Ahead of the vote, the BBC's North America editor Justin Webb said the state's voters had the power to keep Mrs Clinton's White House dream alive by giving her a substantial victory, to do it further damage by delivering a close result, or to destroy it by handing a win to Mr Obama.

Mr Obama said he had made progress against the favourite, Mrs Clinton

On TV on Tuesday, Mrs Clinton predicted victory, by whatever margin, and said if Mr Obama failed to win it would call into question "his ability to win the big states".
Mr Obama conceded that his rival "has to be heavily favoured to win" in Pennsylvania, but dismissed the big-state argument, saying there was "no chance" of the Democrats losing New York or California in the presidential election, no matter who the candidate was.
The Republican Party also held a primary in Pennsylvania on Tuesday, with presumptive nominee John McCain set to take all the delegates on offer.
Senator McCain spent the day in Ohio - expected to be a key battleground state in November - where he spoke of the need to create new opportunities to replace lost blue-collar jobs.