Due to the increasing attacks on the supply lines to Afghanistan from the port of Karachi in Pakistan through Quetta to Kandahar and through Peshavar to Kabul, the U.S. looked for new supply lines. These were found in the north.
Predictably those new supply lines are now coming under attack.
It is obvious that there were absolutely no adults in the room when the campaign to attack and occupy Afghanistan was concocted.
Magical thinking, coupled with a complete ignorance of the Afghan people and their history, created a quagmire from which the US cannot possibly emerge "victorious", from a military perspective.
The old Soviet Union was unable to do this with 500,000 pairs of boots and the ground: the total US and NATO military strength is only a fraction of that.