WASHINGTON — We have heard a great deal recently about the “foreign fighters” flocking to take up arms against the government of Bashar al-Assad in Syria’s civil war — and the threat they may pose if they eventually return to their home countries as battle-hardened jihadis.

The numbers certainly demand our attention. Of an estimated 5,000 to 10,000 foreign fighters in Syria, as many as 2,000 are said to be European nationals, as well as some 100 Australian citizens and several dozen American passport holders, according to published sources. While some are fighting alongside “moderate” rebel groups such as the Free Syrian Army, most have reportedly joined the ranks of the militant Jabhet al-Nusra and the formerly Qaeda-linked Islamic State of Iraq and Syria, or ISIS.

I know the mentality of these nationless combatants. I fought beside them.

As a teenage Afghan refugee living in Pakistan in the 1980s, I joined the anti-Soviet resistance. I took up arms in a cause we called jihad, or holy war — but one focused on liberating our homeland, not exporting an ideology. War came to us through Soviet invasion: We hated it, and we wanted to live through it to see a free Afghanistan at peace.

Pitting a small, impoverished Muslim nation against an infidel invader, Afghanistan’s conflict attracted up to 20,000 foreign fighters in the 1980s, the largest contingent drawn to any Muslim country in modern history. Made up mostly of Saudis and Pakistanis, the army of volunteers also included Egyptians, Tunisians and Indonesians, among others.