MANCHESTER, N.H. — Republican Donald Trump and Democrat Bernie Sanders swept to victory in Tuesday's New Hampshire primaries, adding crucial credibility to their upstart candidacies and underscoring the insistence of voters in both parties on shaking up American politics. While New Hampshire is known for its political surprises, Trump and Sanders led in the state for months. Still, both needed to deliver on expectations after second place finishes in last week's lead-off Iowa caucuses, where Ted Cruz topped the Republican field and Hillary Clinton narrowly edged Sanders in the Democratic race.