This is a moment of complete disaster for Afghanistan and for families across the country. The failure of the US to stay the course has challenged the credibility of American power and could have repercussions thousands of miles away. The precipitous withdrawal is a demonstration of a lack of the strategic patience essential to being a credible ally. We have pulled the rug from under the feet of our Afghan partners and others are watching. Many of us gave all we could and for some the toll was impossibly high. The operation tore families apart, left children orphans and parents to cry alone. For me, the memory that will haunt me every time I carry my child is that of a father I saw carrying his bloodied daughter as he desperately looked for help. Over two decades, through failures and hardship, we had changed the odds. It stopped being the US or Nato fighting the enemy, but instead the Afghan police and army. We built trust and gave the support they needed to sustain operations. We trained these forces to fight as we do, not just with us. We helped them to learn the strength of slim supply lines, air power, and the ability to partner with allies. Our air support and logistics chains provided the capability to succeed. US contractors serviced the helicopters we used, and supplied the weapons we all shared. That made us interoperable in battle, and made the Afghans dependent. So when those contractors were withdrawn as a result of the withdrawal deadline, the helicopters were grounded and the air support gone. Without that, our allies were left outmatched and untrained for what was to come. Worse, our presence was a force multiplier. Nato 10,000-strong deployment was the spine of the Afghan security forces, giving confidence of an enduring commitment to the almost 400,000 Afghan police and army. For us, that’s an efficient force ratio of almost 40:1 and it gave us time to train up the logistics and technical skills for complex kit. That all gave the alliance the sustainable standoff that saw Afghan civic institutions grow, slowly, in the shadow of a government that was learning the ropes. It was not perfect but time was allowing the culture of cooperation to sink roots into communities across the nation. Earlier this year, Kandahar, the capital of the south, had girls’ schools, colleges and opportunity. But, instead of waiting like we did in Germany, South Korea, Japan and Cyprus, we have pulled out. The 2,500 US soldiers that were pulled out of Afghanistan were barely a tenth those deployed constantly in the Gulf and, since combat operations ceased for the Nato troops a number of years ago, barely at greater risk. The last British soldier killed in combat died in 2013 and it has been a few years since US troops had been engaged in combat. Those few thousands of troops that were left were knitting together the army and police that held the state together. Now the future looks all too predictable. We have seen this play out before. Ungoverned space allows for the growth of terror groups such as ISIS that threatened the Middle East, or the East Turkestan Islamic Movement that seeks to break Xinjiang away from China, both of which have been reported to be active in Afghanistan recently. Could this be America's Suez moment – that point when it demonstrates to the world it no longer has the will, or perhaps ability, to play the role it has held for the past 80 years? America's allies and friends will hope not. US leadership is essential to the freedoms we enjoy and the prosperity we now expect. Whatever this is, it’s a massive step change in US, and Nato, credibility and it changes the dynamics of our impact around the world. Some allies will question us, and that will leave us all weakened. While our government should be updating counterterrorism plans the first task of administrations in Nato is to update strategic alliances and rethink our commitments to make it clear they matter. While others use loans and arms to buy support, we can open up investment, trade and travel. We can rebuild our partnerships and alliances, as people from every nation demonstrate daily, people yearn for the freedom we offer, not the silence of tyranny, but it will mean investing in supporting friends and building coalitions. It will cost money and take time but the reward is a world of free people to trade with, share our values and not live in fear.