The US can back groups around the Middle East to physically defeat ISIS in individual cities, and given enough time might even militarily expel ISIS from all significant territory they hold. A new report from the US Institute of Peace, however, is warning that’s not going to defeat ISIS.

The report cites a panel of experts who are saying largely what locals in Iraq and Syria have been warning about throughout the ISIS war, that the group’s territory gains weren’t just happenstance, and that sectarian tension and economic woes that played a big part in setting the stage for ISIS’ rapid rise remain not just unsolved, but largely unchanged.

Predictably, since the Institute of Peace is a US government think-tank, their proposal is that the US government do more intervening in non-military ways, i.e. nation-building, with an eye toward a lasting defeat, which they concede will take many years at any rate.

It is still noteworthy that the think-tank’s report doesn’t envision victory in any meaningful time-frame. The report also noted that President-elect Donald Trump’s campaign proposal to “bomb the shit out of” ISIS was not only unlikely to help, but was likely to make things worse, cautioning that the larger the military intervention, the bigger the jihadist reaction would be.