Presumably, since the United States is a large country in many of its international markets, a positive optimum tariff exists for this country. It follows therefore that when any legislator or government official who promotes zero-tariff free trade policies, is by definition not acting in the public's best interest. Discuss.

It is true that a positive optimum tariff exists for the United States because it is a large country when compared with its international partners.

If the United States uses its size and positive optimum tariff advantage to impose tariffs on imports, other countries are likely to retaliate by following its footsteps.  This does not benefit any country in the long run.

Every forward-looking country that appreciates the benefits of free trade to its citizens is always careful to impose the optimum tariff on imports.

Explanation:

A tariff-imposing nation that is large enough to make some impactful difference in its welfare by imposing an optimum tariff will surely harm its partners so greatly that it will attract some retaliatory moves by the other nations. Likewise, a zero-tariff policy is counter-productive to the public interest as it harms the U.S. productive sector, jobs, and gross domestic product.  This then calls for a balance and a cost minimization strategy.