THE SENATE and House are fitfully considering bills to change the political status of Puerto Rico, but with an important difference. Both chambers would authorize a referendum in which Puerto Rican voters (whether those in the United States as well as on the island is a question) would choose among independence, statehood or some continuing version of the present mixed commonwealth status.

But under the Senate bill, the referendum would be self-executing, which is to say that the result would supposedly take effect automatically, without further legislation. Under the House bill, by contrast, Puerto Rican voters would express their preference, Congress would then pass implementing legislation, and the voters would have the choice of ratifying that.

The House approach is better. Any change in status for several million citizens as contemplated in these bills is going to be enormously complicated. The House procedure leaves needed time to think these complications through and work them out. The status issue is important in its own right. Puerto Ricans are U.S. citizens but have neither all the rights nor all the obligations of citizenship. The threshold question for them as for the U.S. public and Congress is whether that incomplete status is fair. The highly charged status issue often also becomes a part of, and an impediment to solving, the serious economic and other more tangible problems on the island. If by Caribbean standards Puerto Ricans are relatively well-off, by U.S. standards they are left behind.

The problem is that, up to now, almost no one in Congress has really focused on the Puerto Rican question. The island politicians, including the reigning commonwealthers who now regret it, all calculated that it was to their advantage to urge a referendum. The limited progress of the legislation has been a source of great excitement on the island. But here it has barely been a legislative footnote.

That is why the Senate bill is premature. It would lock in place an answer before most Americans -- and most members -- were alert to the question. If the island became a state, would Congress really want (and would it be bound?) to phase out the special tax breaks on which the economy is based? What would be the effect on the island economy -- wages and prices, for example -- of suddenly paying full U.S. benefits there? What would happen to the Spanish language? None of the issues is insuperable, but all need to be addressed. The House bill contains the more orderly process. It's not clear that Congress, in its manifest disinterest, has left time for passage even of that. What better proof of the need to proceed with greater care?