Hillary tried to show off her experience — and distancing herself from her husband's administration — by saying that such forceful action needs to be undertaken with care, noting that the Clinton administration made the mistake of attacking a chemical plant in the Sudan and missing al Qaeda.
Yet she flexed some muscle by warning that "every state must know that we will retaliate against those states that are safe havens for stateless terrorists" and predicting "heavy retaliation."
Richardson raised some eyebrows by stating his belief that Pakistan's embattled President Pervez Musharaff should step aside in favor of a caretaker government of technocrats.
This was the first debate to take place since Thursday's stunning results in the Iowa caucus.
The latest WMUR/University of New Hampshire tracking poll has Clinton and Obama locked in a tie at 33 percent of likely voters.
"This is the one opportunity she'll have," a top Clinton aide told the Huffington Post before the debate. "With just three days to go, she can't go negative on TV. The debate is the only mega news event we've got."
Edwards, who snatched second place from Clinton in Iowa, came in third in the poll and Gov. Bill Richardson, D-N.M., polled a distant fourth at 4 percent.
All day long, each candidate barnstormed the state, insisting he or she was the only true advocate for change.
Eager to take the mantle back, Clinton focused on being "ready to make the changes that America deserves," and on a "new beginning" at the 100 Club dinner in the Hampshire Dome, in Milford this morning, reported ABC News' Eloise Harper and Sunlen Miller.
Yet, Clinton didn't get the best reception from the crowd and was booed by some in the audience who chanted "O-BAMA."
And Edwards told supporters, "The status quo is yesterday. And change is tomorrow. And tomorrow begins today, right here in New Hampshire."
Missing in action from tonight's debate was Rep. Dennis Kucinich, D-Ohio, who didn't make the cut under ABC's rules and has filed a Federal Election Commission complaint against the network.