China has been aggressive in asserting claims in the South China Sea area, and has built islands on reefs and militarized those facilities. In June 2012, then-Defense Secretary Leon Panetta visited the USNS Richard C. Byrd in Cam Ranh Bay - the logistics hub of US forces during the Vietnam War. Taiwan, Malaysia and Brunei also have claims in the sea.
Since 2014, China has forged ahead with island-building in the disputed waters, despite a landmark ruling in 2016 by the Permanent Court of Arbitration in The Hague, which said there was no legal basis for China's maritime claims. Without referring to China's one-belt-one-road (OBOR) that has raised hackles in many countries including India, both sides made a decision to focus on an alternative connective mechanism. That dread is rooted in China's growing military muscle and regional economic influence as well as the increasingly acquiescent policies of other regional claimant states, namely the Philippines under pro-China President Rodrigo Duterte. "I think we've helped create the environment that has allowed for the 70 years of growth".
USA military ties with Vietnam have deepened since 2016, when Obama lifted the decades-old embargo on United States arms sales to the country as part of his Asia pivot.
It has also sought to join the Transpacific Partnership Agreement (TPP), now resuscitated as TPP-11 (minus the United States), in order to expand its export markets and sources of capital and technology.
In addition to Vietnam, the USA is also tightening military cooperation with long-standing allies Australia, Japan and India.
A US Navy band will play a concert in Danang during the Vinson's visit, and sailors from the carrier are to spend time at a treatment centre for people who were exposed to Agent Orange chemicals during the war. The port call will mark the largest USA military presence in Vietnam since the nearly two decade-long war ended in 1975.
"The Philippines has just rolled over, China is continually militarizing and if the U.S. doesn't maintain a presence in the region, Vietnam's got nowhere to hide", Thayer said.
On Friday, a Chinese Ministry of Foreign Affairs spokeswoman said that she hoped that the visit can "play a constructive role for the region instead of making the regional countries feel anxious".
The Nimitz-class supercarrier, accompanied by a carrier and a destroyer, anchored off the coast of Da Nang - the city where 3,500 Marines landed in March 1965 as the first American ground troops in a conflict that would eventually leave 58,000 Americans and millions of Vietnamese dead.
Historical animosity towards China runs deep in Vietnam, which was occupied by its much larger neighbor for much of the first millennium AD.