Sen. Hillary Clinton, D-N.Y., has won the Pennsylvania primary vote as expected with a decisive 10-point win.
The victory was "very big and very sweet," Clinton said today on ABC's "Good Morning America."
"Some people counted me out and said to drop out but the American people don't quit, and they deserve a president who doesn't quit, either," Clinton told supporters at a victory rally Tuesday night after walking out to Tom Petty's song "I Won't Back Down."
"We were up against a formidable opponent who outspent us 3-1... trying to knock us out of the race," Clinton said of Sen. Barack Obama, D-Ill. "Well the people of Pennsylvania had other ideas today."
Clinton told "GMA's" Diane Sawyer that the win should send a message to unpledged superdelegates.
"The road to the White House does go through Pennsylvania," she said, adding that Tuesday's win proves that she can win the large and swing states, crucial to a November victory.
But Clinton declined to endorse a call to let undecided superdelgates pledge to whoever wins the popular vote, where Obama still enjoys a half-million vote lead.
The pressure was on Clinton to win by a large margin and she delivered. With 99 percent of the precincts reporting, she won 55 percent of the vote, to Obama's 45 percent
Obama briefly congratulated Clinton in a speech in Evansville, Ind., but then turned to his common theme of the need for change in American politics and to attacks on Republican John McCain.
"After 14 long months, it's easy to forget this from time to time -- to lose sight of the fierce urgency of this moment," he said. "It's easy to get caught up in the distractions and the silliness and the tit-for-tat that consumes our politics; the bickering that none of us are immune to, and that trivializes the profound issues -- two wars, an economy in recession, a planet in peril -- issues that confront our nation."
Clinton's Pennsylvania victory fuels questions about why Obama hasn't been able to sew up the nomination, despite having more money, having won more states and having a lead in the popular vote and pledged delegates, according to ABC News' delegate scorecard.
With neither candidate able to get the 2,025 delegates needed to win the party's nomination, tonight's win in Pennsylvania will bolster Clinton's argument to superdelegates — the 795 Democratic party officials and members of Congress who may ultimately decide the nomination.
As the results pour in, pundits, Democratic superdelegates, and the media will characterize whether Clinton won by a large enough margin of victory. Devine and other Democrats have long argued the New York senator needed to win the Keystone State over Obama by double digits, and dig into Obama's delegate lead.
"If she wins by 10 points or more, it will be viewed as a clear and convincing victory, but if it's closer than that, it will be less than a clear and convincing victory," Democratic strategist Tad Devine said.
Speaking to reporters in Conshohocken, Pa., Tuesday, Clinton rejected that common argument, saying "a win is a win."
"But maybe I'm old fashioned about that. But you run a very competitive race at a considerable financial disadvantage. I think maybe the question ought to be why can't he close the deal?" she said. "Why can't he win a state like this one, if that is the way it turns out?"