With a display of enthusiasm that surprised everyone, Iowa voters last night began a long process. By the time the presidential primary season ends June 3, Iowans still will have one more event to complete their delegations to the national conventions.

For the Democrats, the outlines of that delegation are clear. It is likely to be overwhelmingly for President Carter. For the Republicans, things are murkir.Last night's Republican results, because of the way the party conducted its caucuses, may bear little resemblance to the actual makeup of the delegation in Detroit.

But as the starting point on this year's political road map, the Iowa precinct caucuses received the kind of special attention accorded any opening point.

That's why the candidates spent up to the limits in Iowa, why the major newspaper had teams of reporters running around the state all month, why Walter Cronkite was on live from the Des Moines Civic Center at 11:30 p.m. And that in turn was why the results will take on greater significance than they otherwise might deserve.

The battle in Iowa was for much more than the 37 Republican and 50 Democratic delegates at stake.

As the polical analysts sift through the vote tallies, the precise order of finish, especially among the Republicans may be judged to be less important than the spacing between them. In other words, if the Super Bowl had been played under the rules of the Iowa caucuses, the Rams would have "won" for exceeding expectations.

One other thing to remember about Iowa: It was the beginning. Not the end.