I can think of several thousand reasons why this idea is impractical in the real world, but ... any government that can dictate the actions of aircraft owned and operated by citizens and corporations of other sovereign nations (i.e., "You can't smoke on your airplane because we say so.") is certainly capable of dictating that no American-owned (in whole or in part) corporation, individual, or other entity pay more than $50 for a barrel of crude oil.
If (and that's a big "if") the United States government passed and enforced such a law, Americans would face immense shortages in the short term, but I do not believe that China and other nations can replace the market lost when oil producers are no longer selling to the United States. Hence, oil producers would eventually give in to the lower prices in the long run--and grant them to other markets. Better to take less per unit than sell no units at all.
And they would still be making fortunes daily.
Again, there are several thousand reasons this is impractical--individuals, corporations, and other entities who have an interest in oil prices remaining high. If, however, we could get China to do the same, it might actually succeed.