That would be insanity on the part of Moscow "leaders", but you never know with those guys.
When Ukraine gave up nuclear weapons in 1996 (as the world's third largest nuclear power) and transferred the weapons to Russia at the American insistence, both the United States and the Russian Federation gave Ukraine "security assurances". If Russia breaks its promises, the US would be morally obliged to defend Ukraine.
US says it will support Ukraine if threatenedThe Associated Press
Friday, September 12, 2008; 3:51 PM
KIEV, Ukraine -- A senior U.S. diplomat said Friday the United States would back Ukraine in case of a territorial dispute but Ukraine's defense minister said his country's role as the main natural gas conduit to Europe makes a conflict with Russia unlikely.
The recent Russia-Georgia war has aroused concerns in Europe and ex-Soviet republics such as Ukraine about Moscow's regional ambitions. The Kremlin has watched warily in recent years as Ukraine and other former republics have sought closer Western ties, and Moscow vehemently objects to their joining NATO.
Although Russian leaders insist they recognize Ukraine's borders, some nationalist politicians have suggested that Russia should regain control of Ukraine's Crimean Peninsula, a jewel of the Russian empire and home to a key Russian naval base.
U.S. Assistant Secretary of State Daniel Fried pledged Friday that the United States would back Ukraine in a territorial dispute.
"The United States, and I daresay Europe as well, support Ukraine's independence, its freedom, its democracy, its right to chose its own future," Fried told reporters after a meeting with his Ukrainian vounterpart.
"Our support for Ukraine has only increased as the result of pressure and will only increase if there is pressure from other places," Fried said. "I hope that no one puts Ukraine's territorial integrity into question."
Fried's remarks echo comments made last week by Vice President Dick Cheney. During a visit to the ex-Soviet Republic, Cheney said the U.S. has "a deep and abiding interest" in the country's "well-being and security."
However, Ukraine's defense minister said during a visit to Denmark Friday that a war with Moscow was unlikely because Ukraine is such an important link in Europe's energy supply.
Asked about a potential military conflict with Russia, Yuri Yekhanurov said he didn't "believe something like this might happen in the future."
A conflict would "have an influence on not only Ukraine but the whole world," Yekhanurov said, noting that 80 percent of the natural gas exported to Europe passes through Ukraine.