Maybe Mr. Greenspan anticipated the EU getting soft with Russia for its natural gas and eventual dependance on it and the Greeks saying screw that.
A history professor one time explained that when Germany and Russia fell out, Germany's war was doomed in that Germany simply could not wage war on the scale planned without Russian petroleum. As it was it ran its tanks on synfuel from coal. Perhaps the same is true for the EU, albeit not war but survival.
The USA are worried about other big nations like Russia.
Greenspan should have tell the truth when he was in command, not now that he wants to set the record straight before he dies.
I'd say it's the EU searching for their Neville Chamberlain not the US.