The demise of dollar diplomacy?

Pundits have been saying last rites for the dollar’s global dominance since the 1960s – that is, for more than half a century now. But the pundits may finally be right, because the greenback’s dominance has been sustained by geopolitical alliances that are now fraying badly…

US diplomatic and military links encourage America’s allies to hold dollars. States with their own nuclear weapons hold fewer dollars than countries that depend on the US for their security needs. Being in a military alliance with a reserve-currency-issuing country boosts the share of the partner’s foreign-exchange reserves held in that currency by roughly 30 percentage points. The evidence thus suggests that the share of reserves held in dollars would fall appreciably in the absence of this effect.

This under-appreciated link between geopolitical alliances and international currency choice reflects a combination of factors. Governments have reason to be confident that the reserve-currency country will make servicing debt held by its allies a high priority. In return, those allies, by holding its liabilities, can help to lower the issuer’s borrowing costs…

South Korea and Japan are thought to hold about 80% of their international reserves in dollars. One can imagine that the financial behavior of these and other countries would change dramatically, with adverse implications for the dollar’s exchange rate and US borrowing costs, were America’s close military alliances with its allies to fray.