IT WAS an admission of a kind that Donald Trump rarely makes. In a televised address to the nation on August 21st, America’s president, reading carefully from a teleprompter, admitted that he had changed his mind about the war in Afghanistan. He said his instinct, after 16 years of not winning, had been to pull out. But after a thorough policy review he had decided to keep going.

That review, undertaken by the defence secretary, James Mattis, and the national security adviser, H.R. McMaster, had been completed by June. But Mr Trump, resistant to its conclusions and egged on by Steve Bannon, a critic of military intervention abroad who was then his chief political strategist, tried hard to find an alternative.

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One scheme, promoted by Mr Bannon and devised by Erik Prince, the founder of Blackwater, a controversial security firm, involved replacing American troops with 5,000 mercenaries. But on August 18th Mr Trump finally acquiesced to the plan set out by his national security team to send around 3,500-5,000 additional troops to Afghanistan. The prospect of Afghanistan again becoming a haven for the world’s most dangerous terrorists had overcome his aversion to fighting a seemingly unwinnable war. It may not have been a coincidence that Mr Bannon was removed from his job in the White House on the same day.

At first sight, the Afghan strategy announced by Mr Trump appears little different from that of his predecessor, Barack Obama. But it has some important—and welcome—differences, which Mr Trump was keen to emphasise while leaving it to Mr Mattis to decide the exact number of troops to send. Mr Mattis, a former marine general, and General McMaster know Afghanistan well. Both have served there. Mr Trump’s new chief of staff, John Kelly, commanded troops in Iraq and lost a son in Afghanistan. They and other American commanders were frustrated and quietly appalled by Mr Obama’s approach to Afghanistan in which troop numbers were cut to serve a domestic political timetable without regard to developments on the ground.

Since the beginning of 2015, when NATO ended its combat mission and handed full responsibility Afghanistan’s security to its ill-prepared forces, the Taliban insurgency has grown in strength. According to a report earlier this year by SIGAR (the Special Inspector General for Afghanistan Reconstruction, a post created by Congress), the proportion of the country under uncontested government control had fallen during the 12 months to November 2016 from 72% to 57%. The attrition of Afghan security forces, say American commanders, is occurring at an unsustainable rate. In the year to November, 6,785 Afghan troops were killed and another 11,777 wounded. The Afghan National Security Forces have 370,000 troops and police. Between 2015 and 2016, 19 Americans were killed in action. Mr Obama had hoped to pull out even the remaining 8,400 American military trainers and advisers before he left office, but eventually he decided to leave that decision to his successor.

Not only will that number now be increased by 50%, but the restrictions on what they can do will be lifted. To minimise American casualties, Mr Obama had set rules that confined advisers to bases far from the action, instead of allowing them to be embedded with front-line combat units where their presence could create what John Allen, a former commander in Afghanistan, calls “an upward spiral of professionalism.” At the sharp end, battle-hardened trainers can help inexperienced officers become competent leaders and develop the skills needed to win fire-fights, among them the ability to call in air support and direct it accurately.

Such skills will come in handy—it now looks as if American commanders will have much more freedom to deploy air power than they were allowed by Mr Obama. Mr Trump declared: “Micromanagement from Washington, DC, does not win battles. They are won in the field drawing upon the judgment and expertise of wartime commanders and front-line soldiers acting in real time, with real authority and with a clear mission to defeat the enemy, we must ensure they have every weapon to apply swift, decisive and overwhelming force.”

A third improvement on Mr Obama’s policy is that Mr Trump has heeded the advice of Mr Mattis that no time limits should be set on the duration of America’s mission in Afghanistan and that any changes in deployments will depend on conditions there. That is of critical importance. As long as the Taliban knew that all they had to do was wait for American and NATO soldiers to pack their bags and go home, there was no incentive for them even to consider political negotiations with Afghanistan’s government. With an open-ended commitment by America, the Taliban’s calculations could change.

But it will remain very difficult for America to reach a point where it can reasonably claim success in Afghanistan. Mr Trump’s insistence that he is not in the business of nation-building is all very well. But without progress by the dysfunctional Afghan government in delivering security and basic services, the Taliban will retain a bedrock of support in the Pushtun south and east of the country.

Nor is there much prospect of enlisting the help of Afghanistan’s meddling neighbours. Mr Trump is right to take a tough line on Pakistan’s provision of sanctuary to the Taliban. But cutting off military aid to Pakistan would be a blunt instrument; in the past, withholding it has had little effect on the country’s behaviour. For all its interest in exploiting Afghanistan’s mineral wealth, China is reluctant to get involved. Perhaps most worryingly, Iran and Russia, always on the lookout for opportunities to undermine Western interests, are now working together to fund, arm and shelter the Taliban. Mr Trump may not care for “strategic patience”, but when it comes to Afghanistan he will need plenty of it.