But now as voters head to the polls here, they appear set to hand both men unlikely victories in the nation's first presidential primary, an outcome reflecting the appeal of political outsiders over well-financed establishment favorites.
New Hampshire's secretary of state is predicting a record turnout in this rare year in which both major parties feature competitive nomination contests. Bill Gardner, the state's top election official for four decades, projected 550,000 votes to be cast across the more than 200 cities and towns in the year New Hampshire celebrates the 100th anniversary of its presidential primary.
That would surpass the nearly 530,000 cast in 2008.
That year Hillary Clinton scored an upset, come-from-behind victory over then-Sen. Barack Obama to keep her candidacy alive through the end of the primaries in June. She hopes for the same this year as polls show her trailing Sanders by double digits here after narrowly defeating Sanders in the Iowa caucuses last week.
"We're going to keep working literally until the last vote is cast and counted, and we're going to go from there," Clinton said during an early-morning stop at a polling place in Manchester.
On the Republican side, the fight has mainly been over finishing second as Trump has maintained his own significant advantage. Sen. Marco Rubio of Florida sought to carry his momentum here after a strong third-place finish in Iowa but has been the target of attacks all week by his fellow Republicans, particularly New Jersey Gov.
Kasich's New Hampshire-centric strategy paid dividends at least in Dixville Notch, the remote voting location in the White Mountains that opens and closes its polls at midnight. He beat Trump 3 to 2, while Sanders swept all four votes cast in the Democratic race there.
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