Democratic presidential front- runner Hillary Clinton promised not to send US troops to war-torn Iraq or Syria if elected saying it would be a "terrible mistake", but refused to give any "blanket statement" on overseas deployment of American combat forces.
"I will not send American combat troops to Iraq or Syria. That is off the table. That would be a terrible mistake," Clinton said.
The US, however, will continue to use Special Forces because of the kind of threats America faces, she told a New Hampshire audience during a townhall organised by CNN.
"The network of terrorist organisations - not just ISIS, but others who are part of this unfortunate network that stretches from North Africa to South Asia - pose serious threats to friends, allies, partners, as well as to ourselves," she said, using an acronym of the Islamic State.
"We have got to keep our country safe, and we have to work with the rest of the world to try to defeat ISIS, to end that terrorist threat. So I will be very careful, deliberate with decision makers when facing hard choices, because I know what's at stake," said the 68-year-old ex-secretary of state.
In response to a query from the audience on overseas troop deployment, Clinton said she can't give a "blanket statement."
"I know you can understand why there can't be from me anyway a blanket statement. But, I want to assure you I will be transparent, I will be open, and I will explain to the American people if any occasion arises where we do have to take military action to protect ourselves or our close friends and partners," Clinton said.
Michael, who is opposed to "the US being the world's policeman", asked if she can assure him that as a president she would not expand US military involvement abroad?
Clinton said she believes military force must always be the last resort not a first choice. "That is one of the biggest differences between me and the Republicans," she said.
"I will do everything I possibly can to avoid sending American troops abroad, getting us involved in military conflicts," she said.
"But I can't in good conscious stand here and tell you that there would never be any circumstances in the time that I served as President where it very well might be in America's best vital national security interest," Clinton said.
Appearing earlier at the same townhall, Sanders emphasised that the Islamic State needed to be defeated.
"For a start, in my view, we have got to crush ISIS," he said.
"But we have to be not just tough, we have to be smart. That means we work with a large coalition, led by on-the- ground Muslim troops. King Abdullah of Jordan made the point, it will be Muslim troops who destroy ISIS, because ISIS has hijacked their religion," he said.
"The US, the UK, France, Germany, Russia provide support, in my view, to the troops on the ground. So we've got to crush them. Internally, what we have got to do is significantly improve intelligence," Sanders said.
