I don't believe trade hurts America. Trade only occurs when it is beneficial to both parties. We would get goods from these Central American countries and they would get dollars. These dollars are only redeemable for American goods made by American workers.
So, how is America harmed?
Forgive me for being so economically ignorant, but if WE can buy goods and services around the world with our dollar, why can't foreigners do the same thing?
Economics 101: the USD is one of two currencies which are completely fungible.
The banana republics can buy oil, French mushrooms, English cars, and Thai hookers with USDollars.
Or ownership of American assets, ownership of American government and private bonds (which is not good for several reasons), purchase of American politicians, courts, legislation, etc., and on and on. It means that, since we don't really have anything to export to them that they aren't already making cheaper themselves (thanks to out outsourcing, manufacturing transfers, etc.) that they will buy controlling interests in America. It also gives them substantial amounts of the "reserve currency" of the world (dollars) which they use to pay for things like oil from Saudi Arabia and goods and commodities from other unfriendly countries (enemies of the US, even if we like to kiss their butts a lot) which further strengthens our enemies. If all they could buy was American goods, there would be little problem from my standpoint.