FURTHER EVIDENCE of the Democrats' indifference to the issues and causes that animated them so fiercely in the 1970s is the response to national party chairman Paul Kirk's call for cancelling the party's midterm conference. Just about everybody yawned. Once upon a time the midterm conference was seen as a chance to change the Democratic Party for the better -- on just how that was to be done there were, of course, about as many opinions as there were active Democrats -- and to show off the party's ideas and candidates. It had begun as a dangerous and -- many thought -- unwise venture that could only highlight the party's mid-'70s strife. But it came to be used as well as a kind of political bazaar: a place for letting off steam and one where rifts of the previous two years might be attended to in advance of an election. Now Mr. Kirk sees the midterm as "a place for mischief," a forum for starting the 1988 campaign too early, and an inefficient use of $1 million of the party's always limited funds.

Each of these reasons parses. Nonetheless it's disquieting to see the Democrats abandoning so soon a forum that has served useful party-building functions. Midterm conferences have accomplished things: in 1974 in Kansas City the Democrats adopted America's first party charter; in 1978 in Memphis they rehearsed the differences over policy (how much should domestic spending be increased -- remember?) between Jimmy Carter and Edward Kennedy; in 1982 in Philadelphia they nearly unanimously signalled that they were no longer a party determined to expand government but rather one determined to maintain it or even prune it back. Viewers saw acrimony and rivalry in varying amounts at each midterm (though little of the former in 1982). But they also got a sense, undistorted by the presidential politics that now utterly dominate the national conventions, of who the Democrats are and what they represent.

The Republicans haven't had, needed, or wanted midterms for party-building: with strong centralized fund-raising operations and neutral, widely acceptable leadership (notably Bill Brock), they have built a strong national party that has won elections and put in office politicians usually willing to back recognizable party positions. They have the advantages of an affluent fund-raising base, a rather narrow range of internal disagreement on issues, and a congenital instinct to close ranks. Democrats, in contrast, have a less affluent constituency, a wide range of views on issues, and an apparently uncontrollable impulse, when beset, to form a circle and fire inward.

So the Democrats have need of any party-building device they can find. The midterm conference has been one of these. It enables activists to sit down and exchange ideas with the myriad of Democratic officeholders who, in Congress and state and local governments across the country, have the day-to-day responsibility for addressing the hard questions of taxing and spending, regulating and leaving alone. Mr. Kirk and the others are right: there are risks and also costs. The question for the Democrats is whether these outweigh the conferences' advantages.