What happens when a major economy can’t pay its debts in dollars?

Russia is about to show us. The problem for Putin’s regime is political rather than financial — that’s why, Adam Tooze argues, this would be no ordinary default. "Sovereign defaults send shockwaves through the global financial system. They signal that a debtor at the very apex of the monetary system — a government — is either unwilling or unable to meet its obligations. Since, in a modern monetary system, government debt is generally treated as the ultimate safe asset, this is a shock that goes beyond the arena of high finance."