Financiers may grumble that the United States is acting like an imperial power in punishing foreign banks for dealings far beyond U.S. territory, but in the end they are more likely to bow to Washington than kick against its dollar muscle.

Last week, French politicians and business leaders demanded an end to the global dominance of the U.S. currency - and hence of the U.S. banking system - after a New York court fined French bank BNP Paribas $9 billion for doing business in Sudan, Iran and Cuba. Yet despite irritation at the long reach of U.S. sanctions, most bankers see that as wishful thinking.