From the earliest days of the Colonies, American-made goods and services have gone out across the seas to virtually every nation. Call it Yankee acumen - or plain old inventiveness - but Americans prospered as they sold their goods overseas.
Now America's commercial eminence abroad is directly threatened: by high interest rates and an overly strong dollar, which make US goods expensive relative to products from other nations; by the stepped-up marketing skills of other trading nations, particularly low-wage Asian producers; and by the day-in and day-out raising of scores of protectionist barriers designed to shore up local industries in many nations by inhibiting the flow of international commerce.
Far too often, such laws are specifically directed against commerce from the United States.
For all their campaign talk about deficits, interest rates, and the American economy, neither President Reagan nor challenger Walter Mondale is yet engaging in a substantive discussion of the underlying challenges to the US standard of living implicit in the mounting American trade deficit. Neither candidate has yet to acknowledge fully that America's long-range financial well-being is directly linked to an expanding international commerce. Neither candidate has fully acknowledged that the changes, the ''downsizing,'' now taking place in many key US industries - steel and autos, for example - are part of a larger, worldwide shift that will continue and most likely intensify, no matter which candidate is elected.
American economic leaders of even four or five decades ago, not to mention the Colonial period, would be astounded at the extent to which the US has become a net importer of goods, services, and capital.
What is clearly needed is a twofold response:
* Some clear talk from the two candidates about America's worldwide trade position.
* Establishment of a long-range Washington policy for renewing America's commercial thrust. Such a policy need not involve a national ''industrial policy ,'' more often favored by Democrats, and generally criticized by free-market-oriented conservatives. At the very least, the US needs a Cabinet-level office that can more explicity coordinate the various trade-related functions now spread throughout the federal government. Virtually every major industrial nation has a far more centralized and goal-oriented trade policy than does the United States.
If trade is considered in this year's election context, Mr. Reagan would seem to have an advantage. Mr. Mondale talks protectionism: He favors a domestic-content law, pushed by big labor, which would require that a high percentage of all cars sold in the US be assembled using US-made parts. Such a proposal could invite retaliation from abroad. Mondale has also unveiled a tougher protectionist policy on steel than has Reagan. He would impose measures to end the ''job-destroying influx'' of imported textiles, garments, and footwear. Such positions reinforce Mondale's support among older Americans - many of whom work in troubled Midwestern industries like steel and autos. This contrasts with Reagan's support among younger voters who look on imports more favorably.
Mr. Reagan's own performance on trade barriers also shows a sensitivity to domestic political calculations: The administration has entered into a number of ''voluntary'' market-sharing agreements; it has often taken a far too blase attitude toward continuing high interest rates, which drive up the value of the dollar. Indeed, Mondale has said he would stress the lowering of interest rates as one way to lower the dollar's value and help boost exports.
The protectionism-trade issue is obviously not a headline grabber. It seems dull.
Forget that. Hundreds of thousands of jobs in the United States are dependent on overseas trade. Jobs held by workers on assembly lines. And farmers. That's the rub.