Atlas V booster flies on Russian engines

Atlas V, one of America's three big booster rockets,  is powered by RD-180 rocket engines supplied by NPO Energomash in Russia.  Aviation Week ran a piece speculating upon the effects of a Russian embargo upon these engines.  Due to worries about the reliability of Russian suppliers, USAF maintains a two year stockpile of the engines.  That's gotta be expensive, although Aviation Week didn't comment upon the expense.  Anyhow  Atlas V could keep flying until the stockpile is exhausted.  And  launches could continue using the Delta IV rocket, which is powered by US built RS-68 engines.  Both Atlas and Delta are built and operated by United Launch Alliance, a spinoff/merger of the booster operations of Boeing and Lockheed Martin.  Pentagon sources say it would cost $1 billion and take five years to set up production of the Russian RD-180 in the US.  Which is prohibitively costly.  They would scrap Atlas V before spending that sort of money. 
   Elon Musk of SpaceX says that his Falcon 9 booster could handle all the launches.  Falcon has made several successful flights to the International Space Station carrying supplies.  USAF is "certifying" Falcon to launch national security payloads.  Certification could happen anytime USAF feels like it.  It's just a paperwork exercise. 
   All three boosters, Atlas, Delta and Falcon are in the same class.  They can all boost the same payloads, give or take maybe 10%.  So loss of Atlas isn't the end of the world. 
   The Russian have made no threats to cut off RD-180 engines.  Presumably they are making good money selling them to the Americans, and they don't want to ruin it.  I doubt that the Russians want to let a little unpleasantness over the Crimea mess up a good thing.