I t’s been a week since Donald Trump suddenly cancelled secret talks with the Taliban, after the Afghan group took responsibility for a deadly car bombing in Kabul.

Mr Trump’s unprecedented negotiations with the Taliban were aimed at ending America’s longest war and bringing US troops home. It’s something the American people have been expecting for a while and both Mr Trump and his predecessor, Barack Obama, have promised to get done, without success. But disagreements remain on how a withdrawal should happen.

The number of US troops in Afghanistan today – around 14,000 – is higher than when Mr Trump entered the White House in 2017. The peace deal with the Taliban was expected to see 5,500 troops withdrawn within five months.

Ending America’s long and costly war is one of the few areas where Democratic candidates agree with the president. The third Democratic debate this week included a discussion on Afghanistan with candidates called on to explain their vision of how to end it.

Senator Elizabeth Warren, one of the leading Democratic contenders, said US withdrawal should start “today” even without a deal with the Taliban. Ms Warren who belongs to the progressive wing of the Democratic party, said what the US is doing in Afghanistan is not helping the safety and security of the United States, Afghanistan or the world. She added that the US military cannot solve the problem of terrorism across the world.

Afghanistan war: lives of children devastated by the endless conflict Show all 20 1 /20 Afghanistan war: lives of children devastated by the endless conflict Afghanistan war: lives of children devastated by the endless conflict Andrew Quilty/Save the Children Afghanistan war: lives of children devastated by the endless conflict Nooria*, 15 in the home her family has lived in for the past two years in Mazar-i Sharif She was forced to flee her home with her family after their town was attacked by armed groups. Nooria describes a rocket hitting her neighbours home killing many inside. They fled on foot with just the clothes on their backs and she now lives in Mazari Shariff where Save the Children have enrolled her in school and provide vocational training Andrew Quilty/Save the Children Afghanistan war: lives of children devastated by the endless conflict Nooria* hopes for a future with no war; "When they attacked our village, the rocket hit our neighbour's house and they all died. Our house then caught fire and we ran away. My friends who I used to play with - I still don't know if they are alive or if they are dead.” Andrew Quilty/Save the Children Afghanistan war: lives of children devastated by the endless conflict “I'm hoping for a better future, to learn, to support my family and to get them out of this difficult life. And I'm hoping for a future where there is no war.” Andrew Quilty/Save the Children Afghanistan war: lives of children devastated by the endless conflict Naveed*, 16 at his family home in Mazar-i Sharif Naveed lost his leg when he stepped on a mine aged just 8-years-old. He was herding the family's sheep in the mountains near their home when he triggered a landmine Andrew Quilty/Save the Children Afghanistan war: lives of children devastated by the endless conflict After months of medical treatment his right leg was eventually amputated. He received physiotherapy and a prosthetic leg from the International Committee for the Red Cross in Mazar Andrew Quilty/Save the Children Afghanistan war: lives of children devastated by the endless conflict Now enrolled in school, Naveed is being given vocational training by Save the Children. “For around a year I felt and dreamt that I still had my leg. But when I woke up and saw, there was no leg. Sometimes I’d feel with my hand to check and find it wasn't there.” Andrew Quilty/Save the Children Afghanistan war: lives of children devastated by the endless conflict “If someone has loses their leg, it does not mean that they have lost their mind." Andrew Quilty/Save the Children Afghanistan war: lives of children devastated by the endless conflict "With the help of our minds we can continue to study, learn, and work to make the future of our families brighter.” Andrew Quilty/Save the Children Afghanistan war: lives of children devastated by the endless conflict Naveed and Mahboob*, 55 (Naveed's father) Several years ago Neveed's father, Mahboob, was brutally beaten with rifle butts by armed groups after, he says, he failed to provide food for them while they were stationed in the family's village. He suffered brain damage which affected the right side of his body, speech and his brain function Andrew Quilty/Save the Children Afghanistan war: lives of children devastated by the endless conflict Habiba*, 14, and Arezo*, 15 in a village outside Kabul Habiba and Arezo were injured with their mother three years ago in a suicide bombing in Kabul. Arezo is still traumatised from what she saw and has become completely withdrawn Andrew Quilty/Save the Children Afghanistan war: lives of children devastated by the endless conflict Arezo's younger sister Habiba cares for her, takes her to lessons and anywhere she wants to go. They are both in school through Save the Children's 'Steps towards Afghan girls' education success' (STAGES) programme, which helps the most marginalised girls get access to education, stay in school and learn. Andrew Quilty/Save the Children Afghanistan war: lives of children devastated by the endless conflict Habiba says: “When I woke up and I opened my eyes I saw lots of bodies and I thought I was not alive any more. It was horrible. I'll never forget that. Whenever there is a big sound she gets scared because she was traumatised by the sound she heard during the attack. I love my sister, and I help her with her lessons, I take her anywhere." Andrew Quilty/Save the Children Afghanistan war: lives of children devastated by the endless conflict "She's older than me but I feel like the older one because I support her. I hope for a better future for me and my sister.” Andrew Quilty/Save the Children Afghanistan war: lives of children devastated by the endless conflict Khalida*, 10 in a classroom in a village outside Kabul Two years ago Khalida lost her 18-year old brother when he was killed in an explosion in Kabul. She misses him every day and says the family are still carrying the grief of his loss Andrew Quilty/Save the Children Afghanistan war: lives of children devastated by the endless conflict "Two years ago, my brother was going to Kabul when an explosion happened and he lost his life. We are still carrying the grief and are crying over him. At the time we were happy, everyone was happy. Now no-one is happy in the family. When I remember him, I cry and feel so bad. I hope for peace and that war will stop, and that nobody loses their brother” Andrew Quilty/Save the Children Afghanistan war: lives of children devastated by the endless conflict “I want to get education to become a teacher. I want to teach others who have never been to school” Andrew Quilty/Save the Children Afghanistan war: lives of children devastated by the endless conflict Sema*,11 at her family home in Kabul Sema recalls coming home from her aunt's house and being told that her father had been killed in a suicide attack Andrew Quilty/Save the Children Afghanistan war: lives of children devastated by the endless conflict Sema still thinks about him every second and likes to look at his prayer beads (Tisbeh) to remember him. They hang from the curtain in the family home. She loves school and wants to become a teacher one day. Sema says she wants peace in her country to stop other children losing their fathers. “We still have lots of his belongings, like his car, his clothes, his watch, his shoes. Whenever we see them we cry. He gave us all so much love every moment and he is on our minds. I want for the powerful people around the world to stop the war and bring peace, because I don't want other children to lose their fathers.” Andrew Quilty/Save the Children Afghanistan war: lives of children devastated by the endless conflict “I want to become a teacher to serve the country and I don't want any girls to be illiterate. I want to teach all the girls, so they have access to education.” *Names have been changed to protect identities Andrew Quilty/Save the Children

Senator Bernie Sanders, one of the most progressive US politicians and a consistent critic of successive administrations’ foreign policy, boasted that he had been the only person on stage to have voted against “all three of Trump’s military budgets”. He said: “We don’t have to spend $750bn [£600bn] on the military when we don’t even know who our enemy is.”

However, critics of an immediate withdrawal of troops from Afghanistan, including senior military officials, believe that ending the long war must be done carefully to ensure that the country does not once again become a safe haven for terrorist groups and future attacks.

General Joseph Dunford, chair of the Joint Chiefs of Staff, has recently warned against withdrawal from Afghanistan as he believes the country still needs support to deal with increased levels of violence. General Dunford has said that the US needs to bring peace and stability to Afghanistan and make sure that the country is not a “sanctuary”.

The Afghanistan war began after Al-Qaeda operatives crashed planes into the World Trade Centre in New York, into the Pentagon and into a field in Pennsylvania on 11 September, 2001, killing nearly 3,000 people. Afghanistan was a base for al-Qaeda and one of the countries where the attacks had been planned, although none of the 19 attackers were Afghans. President George W Bush launched the “war on terror”, which led to the invasion of Afghanistan and later Iraq.

Donald Trump says he could 'wipe out' Afghanistan: 'I could win that war in a week'

During the debate the Democratic frontrunner and former vice president Joe Biden said the US does not need troops on the ground in Afghanistan and suggested that Pakistan can provide bases for US forces to ensure Afghanistan does not become a terrorist haven.

Another candidate for the nomination, Pete Buttigieg, the mayor of South Bend, Indiana, and a veteran who served under General Dunford in Afghanistan, also agreed that the US must put an end to an apparently endless war in a way that ensures Afghanistan is never again used for an attack against the US, but said that it did not require an open-ended commitment of ground troops.

Critics of President Trump believe that negotiating with the Taliban alone can not provide a sustainable solution for Afghanistan.

Ali Soufan, a former FBI special agent who investigated international terrorism cases and is a member of the Homeland Security Advisory Council, says a peace deal must include not only the Taliban, but also the Afghan government and all other political factions in the country. He told The Independent: “At the table we must include the concerns of the democratically elected government, ethnic and religious minorities, women, the security forces, and so on.”

Referring to the chaos of the US withdrawal from Vietnam in the mid-1970s following another protracted foreign war, he added that “to simply just leave could result in another Saigon. We cannot ignore our friends and we cannot ignore the violent fate that would befall them, including from terrorist groups, if we get this wrong.”

Late-night Taliban suicide attack in Kabul hours after US agrees deal to withdraw 5,000 troops from Afghanistan

Nearly 200,000 people have been killed in Afghanistan and Pakistan since 2001, more than 60,000 of them civilians, Brown University estimates. These figures do not include deaths from malnutrition, damaged health systems and environment.

So far nearly 7,000 American and over 600 British service personnel have died in the war zones of Iraq, Afghanistan and Pakistan, in addition to thousands of local military and police deaths. Britain has around 1,000 troops still in Afghanistan.

John Glaser, foreign policy director at the libertarian Cato Institute in Washington, says the argument that the war must continue in order to protect the United States from terrorists is “absurd”.

He told The Independent: “There is zero evidence – zero – that ‘fighting them over there’ has stopped us having to ‘fight them over here’. The idea that a ‘safe haven’ in Afghanistan will somehow enable al-Qaeda or some other group to launch transnational attacks into US soil is largely a myth.

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“Having territory in remote, landlocked Afghanistan just isn’t much help to terrorist groups trying to attack the US, and not one of the jihadi-inspired attacks on US soil since 9/11 was committed by someone with operational ties to terrorist groups within any safe haven abroad.”