Iraqi militias have fulfilled their vow to complete the encirclement of ISIS in Mosul. After capturing Tal Afar airbase last thursday they’ve now taken the last 10 kilometres that seperated them from Kurdish lines further north.
The militias have only advanced on a narrow front so for the time being they remain vulnerable to counter-attack — if ISIS can muster one under under bombs and shells of Iraqi air force and artillery.
Also encirclement over vast swathes of desert can scarcely be airtight. Small groups of ISIS fighters and some supplies will no doubt find ways to sneak through — but not enough to change the big picture.
Initially the largely Shia militias predicted they would connect with Kurdish lines between Mosul and the city of Tal Afar, but in the end they punched through in a way that encircles Tal Afar as well.
The darker aspect of this story is that determined to cut off escape routes for ISIS is partly driven by vengence. Many of the fighters who have now advanced to the outskirts of Tal Afar are natives of the city who had to flee for their lives when ISIS took over in 2014.
In any case, it has ironically been the insistence of Americans that Shia popular militias do not be part of the fighting within Mosul city limits that has left them free to push through well to the west of the city and spoil the US plan to keep an escape corridor for ISIS towards Syria open throughout the battle.