Question

When is a trade diverting custom union is necessarily welfare decreasing for a country

Answer 1

Explanation:

When customs unions are established the flow of trade between countries involved in the new union and those outside will be affected. Customs unions eliminate barriers to trade between members, which is assumed to provide a considerable incentive to increase trade between members and to reduce trade between members and non-members. It is often easiest to appreciate the effect of a customs union by considering what happens when one country joins an existing union