> By that logic every country should continuously weaken it's currency in order to gain an advantage.
It might be an advantage for most people in the country (at least in the short term), but it would be a disadvantage (even in the short term) for the people with the most wealth, and, perhaps more specifically, for the people with the most power over monetary policy.
The advantages (particularly in the near term) that countries get from weakening currency is why the people who loan them money have come to insist than monetary policy should generally handled by independent central banks that are, while generally accountable in some way to government, also somewhat insulated from political pressure from the rest of government (and, often, with direct influence from the financial industry.)
You're missing the point. Every country would like to have a weak currency in order to boost exports. However every country can't have a weak currency simultaneously; it's mathematically impossible. If the USD weakens then other countries will respond by weakening their currencies in a race to the bottom.
We will be better off in the long run by not playing that game. Keeping the currency fairly stable helps to encourage long-term economic growth by allowing businesses and consumers to plan ahead. That's better than chasing a quick and unsustainable boost in exports through devaluation.
It might be an advantage for most people in the country (at least in the short term), but it would be a disadvantage (even in the short term) for the people with the most wealth, and, perhaps more specifically, for the people with the most power over monetary policy.
The advantages (particularly in the near term) that countries get from weakening currency is why the people who loan them money have come to insist than monetary policy should generally handled by independent central banks that are, while generally accountable in some way to government, also somewhat insulated from political pressure from the rest of government (and, often, with direct influence from the financial industry.)