To understand the United States' vested interest in the conflict, you'd have to go back to the Cold War, Craig Albert, an associate professor of political science and the director of Intelligence and Security Studies at Augusta University, told ABC News.
To counter Soviet aggression in Europe, the U.S. helped form the security alliance NATO, or the North Atlantic Treaty Organization, in 1949. In the years since, NATO has expanded several times, including adding three former Soviet republics.
Ukraine, a former Soviet republic that is bordered by Russia on the east, is not a NATO member, though in 2008 the alliance opened the door to membership. Russian President Vladimir Putin has demanded this not happen, as he seeks to limit NATO along Russia's border.
"Ukraine has attached itself to the West, to NATO," Albert said. "They still have military agreements, treaties, economic treaties, business treaties or relationships, even though there's no NATO treaty in place between Ukraine and NATO and the U.S."
The NATO members bordering Russia also present a concern. The potential impact of the Ukraine conflict on U.S. interests is considered "
significant," by the Council on Foreign Relations, which said in part that the conflict "risks further deterioration of U.S.-Russia relations and greater escalation if Russia expands its presence in Ukraine or into NATO countries."
As Russia tries to "reassert itself into the great power game," the U.S. is seeking to maintain the balance of power in Europe and "protect Ukraine as a buffer against Russian-perceived aggression in Europe itself," Albert said, noting that Ukraine is "strategically important" for Russia, the U.S. and NATO.