This is the situation Donald Trump inherited, and his first instinct was to get out of Afghanistan, keeping to the timetable for full withdrawal of the remaining US forces.
In this he was keeping to his words in a tweet of February 2012 when he was first musing about running for the Presidency: “We are building roads and schools for people that hate us.
The Taliban, fed and watered in Pakistan, crossed the border to take advantage of the security vacuum.
American and British troops, part of an international force, were sent back in 2006 for what turned into years of ferocious conflict.
They left in 2014, with a contingent remaining and the declaration that Afghan forces were now fully capable of defending their country.
The US military is hardly proposing a Russian-style deployment in Syria.
It will be around 4,000 additional troops to join 10,000 already there, enabling more to be deployed in combat alongside Afghan forces, provide extra resources for special operations, synchronise air support and monitor the Pakistani border more closely.