The secretary left Andrews Air Force Base, Maryland, on Oct. 19 to assess what is happening on the ground. While it was Esper's first trip to the region as defense secretary, he has made numerous trips there, beginning with one as a soldier serving in Operation Desert Storm.
The secretary also spoke to the leaders of the countries at each stop.
"As appropriate, wherever I go, I want to make sure I reassure our partners that the United States is committed to their defense and, then, how can we work forward to make sure that we maintain the appropriate level of support as we work toward ensuring stability, promoting stability in the region," he said.
The secretary ended the trip in Belgium, where he participated in the meeting of NATO defense ministers in Brussels.
But no matter where he went, the secretary had to answer questions about operations in Syria and the withdrawal of U.S. troops from that nation's border with Turkey. He noted stabilization in the lines in Syria.
He said the U.S. withdrawal is continuing at a fast pace from northeast Syria, and that the process will take weeks.
"We want to be very deliberate and very safe as we go about it," he said.
In Afghanistan, Esper met with President Ashraf Ghani; Defense Minister Asadullah Khalid; Acting Interior Minister Massoud Andarabi and U.S. Army Gen. Austin S. Miller, NATO's Resolute Support commander.
In addition to meeting the leaders, Esper also met with troops.
"I had a good meeting … with President Ghani," he said. "We spoke about the important relationship between our two countries. The United States and Afghanistan have a strong security partnership, built over many years of cooperation and shared sacrifice. That bond was forged in battle, and it grows even stronger as our work continues today."
Esper said the Afghan defense forces are leading their country's defense efforts and have grown more capable.
"The United States remains committed to their success," he said. "I had the opportunity to visit Camp Morehead to meet with the NATO Special Operations Component Command-Afghanistan and the Afghan National Army Special Operations Command. I was impressed by the skill and professionalism of those brave soldiers. Counterterrorism operations have remained critical to our efforts to achieving peace and ensuring terrorist organizations cannot find safe haven in Afghanistan."
He also praised the Afghan forces for their efforts in securing the recent presidential election in the country.
"Regardless of the outcome of the election, our security partnership with Afghanistan will remain strong," Esper said. "Our mission in Afghanistan has not changed. We continue to conduct counterterrorism operations while supporting the development of the [Afghan forces]."
The United States will continue to work toward a political settlement in Afghanistan, the secretary stressed. "Until that is accomplished, we will continue to pursue an aggressive military campaign against the Taliban and terrorist groups that continue to conduct violence against the people of Afghanistan," he said.
When asked if U.S. forces might withdraw from Afghanistan as they are in Syria, he noted the situations in the two countries are very different.
The reason for our withdrawal from northeast Syria was because of the imminent invasion planned by the Turks, a longstanding NATO ally, Esper said. "My concern, and the chairman and the Joint Chiefs' concern, is that our forces would be in harm's way. And we did not want to put our forces in that situation," he said.
In Afghanistan, the situation is different. "We've been here since 2001, since the heinous attacks against America as part of 9/11, and we have now a longstanding commitment to our Afghan partners," Esper said. "We've invested billions upon billions of dollars. Both the Afghan people and the American people have sacrificed treasure and the lives of their soldiers to defend … the Afghan government, the people, and really stand up for democracy and liberty in this country, in this land."
Al-Qaida, ISIS-Khorasan and other terror groups would like to put down roots in the soil of Afghanistan, but the U.S. effort will not let them do that, the secretary said.
"So all these things, I think, should reassure our Afghan allies and others, that they should not misinterpret our actions in the recent week or so with regard to Syria … and contrast that with Afghanistan," he said.
Esper later met the leaders of Saudi Arabia and discussed the threats posed by Iran. The United States sent troops and equipment after Iran launched an attack on a strategic oil facility in Saudi Arabia.
Accompanied by Marine Corps Gen. Kenneth F. McKenzie, the commander of U.S. Central Command, and retired Army Gen.John Abizaid, the U.S. ambassador to Saudi Arabia, Esper met with King Salman bin Abd al-Aziz Al Saud and other Saudi leaders.
He also visited U.S. service members based at Prince Sultan Air Base, where most of the troops are deployed. He reiterated that the United States is helping Saudi Arabia to deter Iranand defend the international rules-based order.
In Baghdad, Esper met with Iraqi leaders — including Prime Minister Adel Abdul-Mahdi and Defense Minister Najah al-Shammar. He also met with U.S. leaders and troops involved in Operation Inherent Resolve.
In Brussels, Esper participated in the meeting of NATO defense ministers. The 29 ministers discussed Syria, Afghanistan, the NATO Mission in Iraq, as well as the deterrence and reassurance missions against Russia and the increasing influence of China.
Esper stressed America's commitment to the alliance. "I want to make clear: the United States commitment to NATO is ironclad; and joined together, we form the most powerful military alliance in the world," he said. "Our willingness to defend one another has been the bedrock of our security since the alliance was first established, and it will continue to preserve our collective security well into the future, provided we commit to investing in it."