Scott Worden, US Institute of Peace, told Forces News, terrorism would have to be a key part "of the risk" to see a return of troops to Afghanistan.
It comes as fighting has intensified between Afghan government troops and the Taliban since US President Joe Biden's announcement that US and other international troops would fully withdraw from Afghanistan by the end of the month.
However, any return of US troops to Afghanistan would be a major gamble with uncertain consequences.
Malcolm Chalmers, Deputy Director-General of the Royal United Services Institute (RUSI), told Forces News there would have to be "a significant reinforcement of American troops" and a commitment "to stay for a much longer period of time".
"I think there would have still been an intensification of the Taliban offensive," he said.
"I don't buy the argument if the Afghan Army had been given another two or three years they would have been a lot better.
"I just don't see that."
Earlier today, Afghanistan's media director was assassinated by gunmen in Kabul, the country's capital city.
Watch: Afghanistan Withdrawal: Should The UK Return To The Country?
It comes days after the Taliban attacked the home of the government’s defence minister, also in Kabul, in the first major bombing by militants in the city for nearly a year.
There has also been increased violence in Lashkar Gar, the capital city of Helmand Province, with thousands of people trapped in the city and aid agencies unable to get in to help.
However, Mr Worden told Forces News "it's not inevitable that the Taliban will just continue at this pace until they take over".
"I think there will be an inevitable swing back toward a stalemate after this initial push when the Afghan forces get more organised," he said.
"There are also resistance forces that are, let's say militias or popular uprisings, that will join the fight."
"I think the bigger concern right now is political and psychological.
"If a certain number of Afghan political leaders think that the government cannot hold, then they may cut deals with the Taliban that cause a collapse before the Taliban actually take over militarily."
Cover image: The Regimental Sergeant Major 3rd Battalion The Royal Regiment of Scotland salutes United States Army General Austin Scott Miller at flag lowering ceremony at New Kabul Compound Afghanistan (Picture: MOD).