(CNN) - China will remain the "primary challenge" to the United States military for as long as a century, warned President Donald Trump's nominee for chairman of the Joint Chiefs of Staff on Thursday.
China had learned from watching the US go to war in the Middle East, and was using those lessons to advance the development of its own military, said current Army Chief of Staff General Mark Milley at his confirmation hearing before the Senate Armed Services Committee.
"China went to school on us," Milley said, responding to a question from Democratic Sen. Tim Kaine of Virginia.
"They watched us very closely in the First Gulf War, the Second Gulf War. They watched our capabilities. And in many many ways, they have mimicked those, and they have adopted many of the doctrines and organizations."
Milley was fielding questions about how he would function as the President's principal military adviser and handle the pressure of delivering his own opinions in the Oval Office.
If confirmed, he will succeed outgoing chairman of the Joint Chiefs, Gen. Joseph Dunford, to become the highest-ranking military officer in the United States and principal military adviser to the President. This transition would come at a time when the Trump administration faces a variety of geopolitical challenges, including the continued expansion of Chinese military power, as seen in areas such as the South China Sea.
"China is improving their military very, very rapidly -- in space, air, cyber, maritime, land domains," said Milley. "They're outspending us in research and development and procurement ... We, the United States, need to make sure that we do not lose our advantages that we have relative to other countries, specifically relative to China."
However, Milley was careful to point out that "China is not the enemy," but instead was a "competitor"
The term "enemy" means "you're at war," he added. "We're not there. We don't want to be there. We want peace, not war, with China."
Kaine wasn't the only senator who brought up questions about China. When Republican Sen. David Perdue of Georgia asked whether China's rebuilding of its military posed a long-term threat, Milley responded, "I think China is the primary challenge to the US national security over the next 50-100 years. I think some historian in 2119 is going to look back on this century and write a book and the central theme of the story is going to be the relationship between the United States and China."
Milley, who was tapped by Trump to be next chairman of the Joint Chiefs last December, has commanded units with the 10th Mountain Division and the 101st Airborne and served multiple combat tours in Iraq and Afghanistan.
After becoming chief of staff of the Army in 2015, Milley helped oversee the army's transition away from large-scale counterinsurgency campaigns in places like Iraq and Afghanistan, focusing instead on near-peer challenges from Russia and China.