It's Easy Enough. If You're Vaguely Connected To Reality.

You bring in force protection first. To secure your exit route in advance.

You don't wait 36 hours until after your total defeat to start thinking about it.

https://abcnews.go.com/Politics/biden-withdraw-afghanistan-chaos-ensuing/story?id=79507930

Although he shouldn't have done.

President Trump was capable of successfully withdrawing US personnel from Syria.

An infinitely more complex battle space than Afghanistan.