PRESIDENT Reagan's trip to China next week - the third time an American president has made that journey - is a symbolic reaffirmation of the vital international political ties that now exist between the two Pacific nations.
Equally important, the six-day visit is expected to reinforce and further the steadily growing bilateral commerce between the two countries. Although total United States trade with China is still modest compared with US trade with other Asian nations - especially Japan - the volume of business activity has been increasing. Many American companies - particularly in electronics, computers, and possibly even nuclear power - could well reach major agreements with Peking during the years ahead.
The presidential trip, of course, comes at a particularly auspicious moment for both nations:
For Washington, the trip gives Mr. Reagan an opportunity to sign at least one , and possibly several, trade accords on a visit that will receive maximum press and television coverage during a presidential election year.
For China, the visit could mean additional US investment funds needed to help Chinese leaders reach their national goal - announced in September of 1982 - to quadruple the nation's gross national product by the year 2000.
What needs to be kept in perspective, as noted by Christopher H. Phillips, president of the National Council for US-China Trade, is that the increasingly durable trading relationship between the two nations was on course well before next week's visit. That is not to say that the Reagan trip will not be useful in furthering commerce. It should do just that. But the point is that the commercial relationship now seems strong enough to survive even momentary political differences, as occurred during the past year over such issues as textiles and continuing US support for Taiwan.
Two-way trade between the two nations is expected to reach at least $5.5 billion this year, up from $4.4 billion last year. It may even be higher if China goes ahead with additional agricultural purchases beyond those now anticipated - and if it steps up its level of high-technology imports. The US last year eased its export restrictions on high-technology products, such as computers. Commerce Secretary Malcolm Baldrige estimates that the new export rules could translate into an additional $2 billion in US sales.
The two nations will sign at least one accord during Mr. Reagan's visit - a tax treaty allowing US companies and individuals to write off on US tax forms taxes paid in China. But both sides should make every good-faith effort to reach agreement on two other pacts: One would promote more US investment; the other would allow the sale of US nuclear power plants to China.
China would very much like a nuclear pact. The issue is complicated, since the US is insisting on retaining controls over nuclear fuel, including restrictions on transfers to third countries. China is expected eventually to commit outlays of up to $7 billion or more for nuclear plants. Various European nations are already scrambling to win that market. Surely a compromise would seem in order between the US and China.