"WHO WILL be vice president?" is not the only question animating the convention proceedings in Detroit. Another question rippling through the political conversation -- sometimes put with apprehension, sometimes with anticipatory giggles -- is this: will be convention, or at least some audiable part of it, boo Henry Kissinger? There has been talk, there are said to be plans, there is even said to be a defensive counterplan on the part of the various Reagan aides and functionaries who would try if not to prevent the delivery of a televised raspberry at least no dissociate the candidate from it and to say something friendly about the celebrated foreign policy maker of the Nixon and Ford years.

It may seem, comparatively, a gossipy and trivial question, one that appeals to the lust-for-trouble instincts so commonly found in those who attend or hang around the psychological edges of the conventions. But in some respects the question is as important as the big, traditional vice presidential one that is hanging over the convention. It is not a concern for Mr. Kissinger's sensibilities that prompts us to say this, but rather a fascination with the Republican Party's own sense of who or what it is -- and with its own willingness (or lack of it) to accept the responsibility for its own record and history.

In an article on the opposite page last Sunday, John Sears observed that Ronald Reagan was distinctive, perhaps unique, among recent presidential candidates for having so keen and relaxed and self-confident an awareness of his own identity. The same cannot be said of the party Mr. Reagan is about to lead. This is not just due to the party's political misfortunes of the past decade, the disgrace and tangle with criminality of both a president and vice president that have caused it to proceed, where writing history is concerned, in the Bulgarian mode: There was no Richard M. Nixon . . . . Spiro T. Who? Other parties, after all, have occasionally turned a portrait or two to the wall, and the Republicans in Detroit can be forgiven for not yet having got comfortable with their recent past in this connection. But there is something more at work.

If you were given to working out overprecise balances in these things, you could say that the Democratic death wish has to do with the clinging to elements of its past that have been rendered obsolete, not just certain programs and assumptions, but even certain animosities and quarrels. The Democrats never throw anything out. The Republican throw out everything. Their death wish has to dowith a continual disavowal and rejection of their own past, a refusal to let their actions in office define who they are. There is said to be some core element of the party that is sore about Henry Kissinger, that sees him as the emblem of Nelson Rockefeller's re current disruption of their intentions, the seller-out of their (out-moded) Taiwan policy, the SALT II softie and so forth. Similarly, John Connally is the one who promoted the Nixon wage-price controls, Howard Baker -- never mind that he is their Senate minority leader -- is the guy who sold out the Panama Canal and a couple of other things. This core element of the party is said to go about in a condition of perpetual betrayal -- it is still "getting over" the Eisenhower breaches of faith and the Nixon years and the latter-day Goldwater softening and pretty well all the rest of its contemporary record.

Around Detroit the anxiety you hear expressed over the prospective booing concerns mainly the image of the party being televised across the land: booing -- a la the San Francisco 1964 disruptions -- may be perceived as evidence that 1980 has brought together a grudge-ridden, nasty, "extremist" crowd. But that's the tinselly, superficial least of it. At some point the Republicans are going to have to own up to their autobiography. It's not good enough to keep saying, after years of govenment leadership in the executive branch and participation in the working of Congress that there is some idyllic, right-wing, 100 percent pure Republicanism existing somewhere that comes together in the chemistry of a convention and expresses the thoughts of those who are thereafter always betrayed.

It's not true. Reasonable (and personable) Republicans, many of whom have served in the Nixon and Ford Cabinets and also in the Eisenhower administration, participate in the Detroit proceedings and give assurance by their conversation as well as by their mere presence that there is a record of conservative solidity and continuity that the Republican Party intends to pursue. Gov. Reagan, to his credit and also his benefit, has mobilized these people in his campaign. A lot of them are not exactly mad about Mr. Kissinger, and some no doubt think Sen. Baker leaves much to be desired, and certain aspects of the postwar Republican governments probably leave them cold too.

But these men and women convey in private and in quiet voices a willingness to acknowledge what the Republican Party has really become and what its offer to the electorate must be if it is to be taken seriously. They are a good advertisement for that party -- which one of these days, is going to have to stop pretending to be something it is not.