America's ability to be a global power depends on the world's ongoing willingness to accept dollars in exchange for goods and services rendered. The dollar was once supported by gold and by unrivaled manufacturing infrastructure. We no longer have either, and the dollar is now supported by the rule that 'no one may buy oil except in dollars'. That rule is supported, in turn, by American sanctions of countries that sell oil for Euros or Yuan, and secondary sanctions on any country that doesn't also sanction the seller. The two culprits at the moment (selling oil on an open exchange) are Iran and Venezuela. We're dealing with Venezuela privately, in our own backyard. The Warsaw summit was convened to deal with Iran. Neither plan is going smoothly.