Army Gen. John “Mick” Nicholson said Wednesday in his last briefing as the top U.S. commander in Afghanistan that President Trump’s Afghanistan strategy was working, citing progress in the peace process, or reconciliation, with the Taliban.

“Ultimately, wars end with a political settlement. So the progress towards reconciliation is key. And the fact that we had been able to make this kind of progress [is] significant,” Nicholson told reporters at the Pentagon.

Nicholson said within six months of the new strategy, there were two peace offers on the table: an open letter from the Taliban to the American people, and an offer from Afghanistan President Ashraf Ghani. He said within ten months, the country held its first nationwide ceasefire in 17 years, over the Eid al-Fitr holiday earlier this summer.

He said the ceasefire “unleashed” pressure from the Afghan public, who are demanding peace. He said Ghani has now offered a second nationwide ceasefire that could last through Nov. 20, the day of Prophet Muhammed’s birth.

“So the progress towards reconciliation, which ultimately is what we want … which will enable a political end to the war, is perhaps one of the greatest successes of the strategy so far,” he said.

Nicholson said he believes what brought about this progress was the Trump administration getting rid of the Obama administration’s timeline for withdrawal, and further commitment from NATO allies to extend security assistance to 2024.

“This has affected the enemy’s calculus. And this is one of the contributing factors to why they’re now willing to — to begin talking about an end of the war,” he said.

Asked by CNN why the current strategy was not recommended sooner, Nicholson faulted the Obama administration’s approach.

“In the time that I joined this mission as the last commander appointed by President Obama, we were on a glide path to reduce our forces and eventually to close down the mission,” he said.

“And so, at that time, the enemy had no incentive to negotiate because we were leaving. So in war, which is a contest of wills, the enemy believed that we had lost our will to win and that all they needed to do was wait us out,” he said.

“I believe the South Asia Strategy is the right approach. And now we see that approach delivering progress on reconciliation that we had not seen previously. And I think that was because we clearly communicated to the enemy they could not wait us out. We were backed up by our allies,” he added.

Nicholson acknowledged that there is an “impasse” on the battlefield in terms of control of territory or the population gained from the Taliban, but suggested it may no longer be the best metric for success.

“We have looked at the same metrics over time. So now, as we begin to change those metrics — things like social pressure, religious pressure, reconciliation — all of these factors are part of the South Asia policy, they are things to be examined. And I think they are things contributing to the progress that we’ve seen towards reconciliation,” he said.

“So I think we’re seeing the strategy is fundamentally working and advancing us towards reconciliation, even though it may not be playing out the way that we anticipated,” he added.

However, he said there has been progress in growing the size of the Afghan commando force from 30 companies to 45. “These commandos are the ones that are able to turn the tide in any fight that they join,” he said. He also said the Afghan air force is now conducting about half of the airstrikes in Afghanistan.

He said recently that over 250 fighters from the Islamic State in Iraq and Syria (ISIS)’s Afghanistan branch, ISIS-Khorasan, and their family members recently surrendered to Afghan forces in Jawzjan in Northern Afghanistan, eliminating one of three “pockets” of ISIS in Afghanistan.

He dismissed the Taliban’s efforts to seize two provincial capitals, calling them failed attempts. “Can they conduct attacks? Yes. Can they hold what they take? No.”

Nicholson said the U.S. is prepared to work with the parties involved to reach a peace agreement that brings about a permanent end to the war, and the State Department has been exploring “all avenues” to advance a peace process, in consultation with the Afghan government.

He said ultimately, any negotiations over the political future of Afghanistan would be between the Taliban and the Afghan government. He noted that the Taliban has not yet accepted or rejected Ghani’s ceasefire offered.

But, he urged, “We have an unprecedented opportunity, a window of opportunity for peace right now, so President Ghani is working to take advantage of it.”

He also cautioned there could be further setbacks, but expressed confidence in the peace process.

“Now, there will be ups and downs, there will be leap-aheads, there’ll be frustrations, there’ll be, you know, two — two steps forward, one step back from time to time, but the process is started,” he said.