The United Nations' position on Syria has been consistent: there cannot be a military solution.

But those words now sound very hollow.

In eastern Aleppo, no one expects a political settlement. Hour by hour, Bashar al-Assad's government -backed by Hezbollah, Iran and the military might of Russia - advances.

The nearly six-year-long conflict in Syria has claimed hundreds of thousands of lives and displaced millions of people.

The man who has led the UN throughout the Syrian war, UN Secretary-General Ban Ki-moon, is in the final few weeks of his 10-year term at the UN.

On Talk to Al Jazeera, Ban Ki-moon discusses the state of the Syrian war and whether there will be accountability for the war crimes committed; his thoughts on the new Trump era and the impact on the international community; and - with his home country South Korea facing political crisis - his future plans.

Come January 1, 2017, when I return to Korea, I will need to discuss with some community leaders and my friends on what and how I can contribute as the former secretary-general of the UN to my motherland Korea.

Ban Ki-moon, secretary-general of the United Nations

"It has been a sad and heartbreaking experience for me to see that the Syrian people have been suffering tremendously during the last five years. It's a collective failure of the international community," says Ban, when asked how history will judge the international community on Syria.

"The United Nations and regional powers should have helped them resolve their problems. But unfortunately regional powers and the United Nations, particularly the Security Council, have been divided. That is why we have not been able to resolve this issue. There is no military solution."

He says he has been reiterating that inclusive, Syrian-led, intra-Syrian dialogue is the only way to resolve the conflict.

When pressed that this line has become a mantra, Ban points to the efforts of UN special envoy Staffan de Mistura, US Secretary of State John Kerry and Russian foreign minister Sergey V Lavrov

We ask Ban what it means that Bashar al-Assad, responsible for such brutality and quite possibly war crimes, should continue to remain in office even after US President Barack Obama and Ban himself will have left their posts.

"Even though the justice cannot be done today, I'm confident that there will be justice," he says, adding that the priority right now should be saving human lives and delivering humanitarian assistance.

We speak to Ban about the future of the International Criminal Court (ICC), and if it loses relevance, whether Assad can be held accountable. Russia has expressed its displeasure with the ICC and African nations have been pulling out, while others are thinking of withdrawing. Ban said he believes that the ICC must be preserved. 

On the issue of US President-elect Donald Trump declaring the UN weak and incompetent, Ban points to the US's long commitment to the world body, saying: "I am sure that President-elect Donald Trump will also continue to play a very important global role in working together with the United Nations in maintaining peace and security and development and human rights."

When asked whether Trump's criticisms are true, Ban says it's important that member states should bring their "global perspectives rather than ... narrow, national perspectives. That is the way why United Nations has often been criticised as inefficient and not being able to make decisions."

We speak to him about the UN's many failures - bringing cholera to Haiti; failing to protect people in South Sudan; and in the Central African Republic, peacekeepers were involved in the sexual abuse of children - and if he feels ashamed that the UN, instead of bringing good, has also brought harm.

Ban says he has expressed his deep regret for the cholera epidemic in Haiti. When it comes to sexual abuse and violations by peacekeepers and UN staff, he says: "I have made a zero-tolerance policies and I have taken immediate actions."

On the question of what he thinks about Trump considering scrapping achievements, such as the restoration of US relations with Cuba, the Iran nuclear deal, and the Paris climate accord, he says he has already spoken to the US president-elect about these issues but does not go into further detail.

We ask Ban about what he'll do next and whether he would consider serving his country, which is currently facing political crisis and widespread protests, if South Koreans call upon him to do so.

"Come January 1, 2017, when I return to Korea, I will need to discuss with some community leaders and my friends on what and how I can contribute as the former secretary-general of the United Nations to my motherland Korea," he said. 

"Of course, I will be relieved of this huge burden, mental and physical. It has been a great privilege for me to have served this great organisation for humanity during the last 10 years. Now as a private citizen, I will still be embedded with such principles and goals of the United Nations on which I have been working, like international peace and security, sustainable development, and human rights.

"As a private citizen, I will try to continue to raise my voice and contribute whatever I can to help the United Nations. At the same time I will also think about what would be the best way for me to work for my own country."

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Source: Al Jazeera