BBC EXCLUSIVE: The Taliban has told the BBC that if 'a single' foreign troop remains on the ground in #Afghanistan beyond the current negotiated withdrawal timetable, they will see them as a legitimate target and their 'jihad' will be resumed. 1/7 https://twitter.com/SecKermani/status/1338416459219931136

This illustrates why #Afghanistan-s going to be one of @JoeBiden-s biggest foreign pol. challenges during his first days in office. Sticking to @realDonaldTrump-s timetable of complete withdrawal by spring brings with it significant potential problems; as does not sticking to it

Arguably leaving hastily weakens Afghan govt position and embolden's the Taliban, AQ and IS-K (ISIS in Afghanistan). He'd also be seen as abandoning @NATO allies, who engaged in a protracted, bloody and costly war after the 9/11 attacks on the US.

NATO Secretary General @jensstoltenberg-s been very clear that the price for leaving too early could be very high. He's against a hasty withdrawal. Unlike Trump, Joe Biden has reaffirmed the US' commitment to NATO.

If @JoeBiden sticks to his own stated view of leaving behind a residual counter-terrorism force in Afghanistan to ensure the country does not again become a haven for terrorism, the war with the Taliban will likely be back on.

In this scenario the President-elect will also have to defend accusations that he has undone the achievements of the Trump administration and destroyed the only real chance of peace in years. He'll be criticised for going back on his word to end America's 'forever wars'.

In the short term, bringing troops home will be very popular at home. And the flailing intra-Afghan peace process *could* be kept on track.

But what then if Afghanistan becomes a haven for terrorists plotting attacks against the West and gains made during the 20 year conflict are undone? Afghanistan will again be the world's problem. Quite the dilemma.