Willingness to fight and make costly sacrifices is also strongly associated with perceptions of physical formidability on the battlefield and, even more importantly, with spiritual strength. My research group found that Nusra fighters consider Iran (by which they also mean Hezbollah) to be the most formidable foe in Syria, both in terms of physical and spiritual strength, but they consider the Islamic State growing to parity on both scores. These Al-Qaeda combatants consider the US to be of middling formidability, and the Syrian and Iraqi armies to be relatively weak physically, and spiritually worthless, and thus an inconsequential enemy in the long run.