If there is a single large and unifying theme to the the midterm election campaigns being waged for Congress and for state and local offices all over the country this fall, it is the taxpayers' revenge. Candidates are falling all over themselves to establish their bona fides as tax-cutters, rebaters and general scourges of politics-as-usual and government bureaucracy wherever either may choose to raise its ugly head. The good news is that al least Proposition 13 fever has compelled a lot of self-satisfied elected and appointed officials to take seriously legitimate public grievance with arrogant, overblown and blowsy government. The bad news is that in many political quarters the reaction has been as mindless and self-indulgent as the practices to which the taxpayers were objecting in the first place.

We are not thinking here of the stampede to get on the winning side or the fact that numbers of politicans have made spin-arounds on the subject of government spending that would make a whirling devish dizzy. Conservatives who complain that their issue has been "stolen" by liberal Democrats will just have to find another shoulder to cry on. That kind of theft has been the political game as long as anyone can remember, and in its way it is even an evidence of success, since it means the (stolen) position has prevailed. If the originators of the tax-cutting fervor couldn't survive their own success, it's too bad from their point of view, but hardly something the rest of us need to put on the national worry list.

There are better things to worry about in this year's political climate. And chief among them is the way so many office seekers are responding to the legitimate message of the fed-up taxpayer with a pandering hymn to greed and encouragement of voters to believe themselves the persuted targets of a deliberate government conspiracy. Yessir - the 1978 siren song seems to go - they have really been doing a number on you. You know who we all mean by 'they.' And meanwhile they are all sitting back getting richer and fatter. And nothing gets better for you. And if you make an honest dollar, they just take it away. And it doesn't need to be like that - not if you elect good old John J. Freelunch to office.

Et cetera. In our opinion it's not the fact that so many liberal Democrats or equally improbable converts have seen "the light" that is disturbing. It's the nature of the light they appear to have seen. There is and has been plenty wrong with many of the programs and much of the policy that liberal and middle-road politicans have put in place over the past two decades. An honest acknowledgement of this fact and a straightforward effort to correct it would be the most welcome development in our politics. But (as it was in California pre -Proposition 13) there was, first, a stubborn unwillingness to concede this much and, then (after the voters indicated they wouldn't put up with it any longer) an uncritical and undiscriminating rush to condemn government and all its works as some great alien, usurping monster that appeared out of nowhere and needed to be whipped back, if not eliminated.

Maybe it is asking too much of election campaigns to wish they would be based on some truths likely to be as valid in March and August as they seemed to be in November. Nevertheless, however the voting may come out in all those thousands of precincts across the country tomorrow, we get a sense that a good thing has been squandered in the midterm elections of 1978 - that an opportunity has been blown. It was an opportunity to have that long awaited (and still awaited ) debate for which the country is overdue on how to reassess the programs and redirect the energy and money that went into the legislative outpouring of the Great Society years and their Republican aftermath.

Put it down as just one more irony, that a new wave of candidates professing not to be politicans and an old wave of politicans professing not to be politicans either, politicized what might have been a real breath of fresh air in our national debate over possibilities and values. What we ended up with most places was a narrow pitch to self-interest defined in the narrowest way imaginable. When all those voter-taxpayers who have been promised what can't be delivered and told it is just being kept from them by a conspiracy of government find out they've been had yet again . . . well, what's going to happen then?