A basic national interest of the United States is to prevent the domination of the Eurasian landmass—the so-called heartland—by one hostile state or group of states. This objective is important to U.S. survival because a hostile government controlling this vast region would have the resources to isolate and perhaps eventually destroy the United States.
Lasater, Martin L.
"Strategic Trends in Asia: U.S. Policy Toward Regional Communist States,"
Naval War College Review: Vol. 42
, Article 4.
Available at: http://digital-commons.usnwc.edu/nwc-review/vol42/iss2/4