The Islamic State of Iraq and Syria (ISIS) for years has benefited from a robust flow of foreign fighters to their ranks, something that confounded many in the West who only saw a blood-thirsty death cult.
That may be changing, however. Recently, Major Gen. Peter Gersten, the Pentagon's director of operations and intelligence for the campaign against ISIS, said that a year ago the U.S. estimated there were 1,500 foreign fighters per month coming into Iraq and Syria. He said that number is now down to 200 per month.
Last week, FBI Director James Comey said that the number of people attempting to leave the U.S. to join ISIS has been down for nine months, and that it appeared to be a general downward trend.
Comey said there are a few reasons -- in addition to the group's mounting battlefield losses -- that this is likely: the aura and fad that came with the group has faded; prison sentences for supporters and members are piling up; and people are realizing how hellish it is to live in ISIS territory.
In January, Brett McGurk, the U.S. special envoy for the global coalition to counter ISIS, echoed the belief among top U.S. officials that foreigners are starting to flee the extremist movement. He said ISIS' ranks of foreign fighters have dropped to about 25,000 from a peak of 35,000.
The extremist group is under constant pressure and has cut fighters' salaries by about half.
The group -- which once bragged about minting its own currency -- is having trouble meeting expenses, thanks to coalition airstrikes and other measures that have eroded millions of dollars from its finances since last fall. Last year both the U.S.-led coalition, as well as Russian fighters, began targeting their oil production capabilities and cash stores.
Those circumstances include the dramatic drop in global prices for oil - once a key source of income. Additionally, the targeted airstrikes have dramatically reduced cash stockpiles and oil infrastructure. And the Iraqi government has stopped paying civil servants in territory controlled by the extremists.
In addition to targeting their image as a cash-rich group, the U.S.-led coalition has also targeted ISIS' slick online propaganda machine.