Advantages of a currency union?

Question

Like the Euro, or a North American dollar.

Disadvantages?

Answer 1

Main advantage of a single currency is the ease of trade and travel within the region of that currency.  Imagine for a second, that someone in New York buying fruit from New Jersey had to deal with two different currencies, or that someone traveling from Virginia had to change currencies when getting off the plane in Massachusetts.  

Main disadvantage is the shift of control over the currency to a higher level of government, which may be less responsive to the needs of the lower government when it comes to monetary policy.

Answer 2

North American Dollar ? no such thing. I think it would give too much control to whoever controlled the single currency. I see nothing good.

Answer 3

The battle cry for the introduction of the Euro was, "One market, one money!"  The idea being that the use of a single currency was a critical prerequisite to the free trade and services envisioned in the European Union.  The single currency can be viewed as a powerful public symbol of unity, and also is said to allow for a single-minded direction in a unified monetary/fiscal policy.  That said, the primary disadvantage is that a single currency shifts control of monetary policy away from the national level, and into a collective leve which may not act in an individual nation's best interests.  The smoothing effect rewards the weaker member nation's, and punishes the stronger.

A North American dollar is not even a remote possibility at this point in time - there is no political impetus for such a shift, as NAFTA is strictly geared toward the simple trans-border movement of goods.