Britain has been at war in Afghanistan for more than 12 years, which must be some kind of record. The media have largely forgotten about it, except when British soldiers are killed.

Barack Obama said last month that the foremost US foreign policy concern was managing the withdrawal of its 62,000 troops. A Taliban political office in Doha was formally opened following long negotiations but promptly closed, apparently because of a row over its use of the name and flag of the 'Islamic Emirate of Afghanistan'. Coming back from a visit to Afghanistan, David Cameron welcomed the prospect of dialogue between Hamid Karzai's government in Kabul and the Taliban, but Karzai has called off the negotiations because of the row.

On Monday, the New York Timesreported that a videoconference between Obama and Karzai designed to defuse tension ended badly, with Karzai accusing the US of trying to negotiate a separate peace with the Taliban, leaving Afghanistan exposed to its enemies. Obama was said to be giving serious consideration to speeding up the withdrawal of US forces and to a 'zero option' that would leave no American troops there after next year. Yesterday, the State Department spokeswoman Jen Psaki told journalists:

I did read the story this morning, of course. We are committed – let me just – bear with me here, just to give you a broad overview of our approach – to continuing to support a fully sovereign, democratic, and united Afghanistan. We have been clear in public and in private, as have many of our allies and partners in ISAF and in the broader international community, that we do not intend to repeat the mistakes of the 80s and 90s, and that as the Afghans stand up they won’t stand alone.

As you know, this is a decision that the President will make. He is still reviewing options from his national security team and has not made a decision about the size of a possible US presence. He’s considering a range of options, as you know, and we made clear as far back – made that clear as far back as January. So any report stating a decision is being made, or has been made, I should say, is inaccurate.

QUESTION: But there is a zero option; that’s one of the options still on the table?

MS. PSAKI: That has been an option that has been on the table for quite some time.

QUESTION: So has it moved up the pecking order from number one, two, three, four? Has it become one of the more serious options?

MS. PSAKI: I would point you to the White House for that. This is a decision the President will make.

Connoisseurs of bureaucratic fencing matches may like to read more, as Psaki avoids answering further questions, for example which particular mistakes of the past are not going to be repeated.

The NYT report goes on to comment:

The ripple effects of a complete American withdrawal would be significant. Western officials said the Germans and Italians — the two main European allies who have committed to staying on with substantial forces — would leave as well. Any smaller nations that envisioned keeping token forces would most likely have no way of doing so.

The UK has the largest contingent in the Nato/ISAF mission after the US. Last year, in response to a suggestion that we are in Afghanistan to preserve our relationship with Washington, I wrote that 'the US will decide when to leave Afghanistan for its own reasons, and will not be influenced by concern about Britain,' but I failed to forecast that the NYT would forget that the British are there. I also questioned whether loyal support for America would somehow be rewarded, and lack of it penalised. Since then, François Hollande campaigned on the promise that he would withdraw French forces from Afghanistan, and as president has in fact withdrawn them, without incurring any criticism let alone penalty so far as I am aware.

According to Downing Street, 'we are in Afghanistan for one overriding reason – to protect our national security by helping the Afghans take control of their own.' If that is to be taken at face value, a US decision to go for the zero option would be unwelcome to the UK, and London would be urging Washington to stay. How likely is that?

The Foreign Office and MI5 have long argued that participating in the war does not protect but damages our security by inspiring extremism. The director general of the Office for Security and Counter Terrorism told a National Security Conference in London last week about the danger that people from Britain fighting in Syria and inspired by al-Qaida may return to organise atrocities here, but he appears to have mentioned Afghanistan only in passing and in the past tense.