HERE'S A New Year's resolution for Congress: pass campaign finance reform. The deed almost has to be done, if at all, in an odd-numbered year, and no issue of comparable importance will be on this year's agenda. The budget should not take as much of this session as of the last 10. The skirmishing is more likely to be around the edges of fiscal policy than at the core. The budget agreement also all but rules out major new programs. That leaves improvement of existing processes, and none is more important than campaign finance, which is where it all begins. This is Congress' own issue, on which increasingly it has no place to hide.

The problem is that the price of office has been bid too high. A Senate seat can now cost $15 million; the average winner spends more than $4 million. The average House winner spends more than $300,000, which sounds a lot less but is nearly the same when adjusted for size of district (on average, less than a fourth as large) and length of term (a third as long).

The need is for spending limits, which for First Amendment reasons have to be voluntary. Candidates have to be induced to comply, and the best way is through an offer of partial public financing to volunteering candidates, as is already done with no evident ill effect in presidential campaigns. Along with spending limits there is probably a need, on the House side particularly, for limits on the role of PACs, the giving arms of interests groups to which too many sitting members now confidently look for more than half their funds.

Resisting Republicans claim to be against even indirect public financing on principle. But they register no loud objection to it at the presidential level. Why is it wrong at the one and not at the other? They also claim that spending limits would make the process less competitive rather than more, disadvantaging challengers (mainly Republicans in a Democratic Congress), who must often outspend in order to win. But the truth is the opposite. Spending limits can only increase competitiveness, again particularly in the House, where the Democrats have their strongest hold, the reelection rate is highest and incumbents, thanks to the PACs, were most recently able to outspend their challengers by nine to one.

That's a major reason why too many House Democrats (and comfortable Republicans as well) don't much want reform. Who's to blame them? The House Democratic leadership did force through a not-bad bill last year after Senate Democrats (and five Republicans) passed a better one. But the legislation never went seriously to conference; the House Democrats didn't have their hearts in it. They ought to, if only to stave off term limitation, a bad idea for which the present clubby system of finance is one of the few good arguments.

The argument is made, and not just by the present system's keepers, that as long as you have willing donors and recipients, campaign finance reform will never work. Nor perhaps should it even be tried, since the money will always find its way, reform will beget only subterfuge, and the government will be forced to over-regulate a process better left alone. There's truth to that, but it's not a paralyzing objection. No reform lasts forever, and the goal of this one is not an antiseptic government. A moderate amount of reform can achieve a moderate reduction in the role of money. That's all that is wanted.

You can also hear the argument that this is the wrong cycle for reform, that House members already anxiously watching while their districts are redrawn for the 1992 elections can hardly be expected to change the financing system at the same time. Later will be better, it is said. But for those whom reform is likely to touch, later is always better. Congress is bought now; that is at least the appearance, if not the reality. It lives with hand outstretched for campaign funds. The system is demeaning as well as dangerous, and this is the year to change it.