Baghdadi had led ISIS (Islamic State of Iraq) since 2010. In 2013, he announced the establishment of the Islamic State of Iraq and the Levant (ISIL), and a year later, Baghdadi declared the formation of the worldwide caliphate with himself as caliph. At a high point in 2015, ISIL had control of areas in western Iraq to eastern Syria, including the Iraqi cities of Fallujah, Ramadi and Mosul, with more than 10 million people, an annual budget of more than $1 billion and more than 30,000 fighters. A U.S. led intervention coalition formed in late 2014 began the fight against ISIL. But, it took until 2017 to win back Mosul. By the end of 2017, ISIL was down to a handful of areas under their control in Syria.
Declaring ISIS defeated, President Trump first announced the U.S. withdrawal from Syria in December 2018 (Secretary of Defense Mattis resigned) and later repeated the order in October 2019.
America has been announcing the end of Middle East operations for decades. President George W. Bush thought the end of combat operations in May 2003 (Mission Accomplished on the USS Abraham Lincoln) was a conclusion to the Iraqi war. After Osama bin Laden’s death in April 2011 and progress in the transition to the Iraqi government, President Barack Obama withdrew the last of America’s combat troops out of Iraq in late 2011. Later, he failed to enforce a red line in Syria in August 2012. But, reluctantly, Obama had to restart air and ground operations in the fall of 2014 to deal with ISIS.
Unfortunately, the Middle East has a long history of drawing us back into combat operations.