THE HOUSE'S REPUBLICANS and 69 of its Democrats did good work Tuesday when they shelved the campaign regulation bill. The bill's worst feature had been a Democratic attempt to counteract the Republicans' fund-raising success by sharply curbing political parties' contributions to House campaigns. After muscling this partisan amendment through the House Administration Committee, chairman Frank Thompson (D-N.J.) and his allies did promise to delete it on the House floor if the GOP would agree to bring up the bill. Apparently fearing more mischief, the Republicans refused and voted as a bloc against considering the bill at all.

The other target of opposition was the plan for public financing of House campaigns, which a bipartisan coalition, spurred by Common Cause, had been poised to offer on the House floor. The backers of this plan may try to revive it and are already describing its shelving this week as a blow to "reform." So lets look at a few of the "reforms" it would involve.

For one thing, public financing is often praised as a way of "opening up the system" and making campaigns more competitive. The House plan could have the opposite effect. I would offer public funds to match small individual gifts to House campaigns, up to $50,000 in subsidies per candidate. That would help poorly financed candidates get some messages to the voters. But it would not apply to primaries. And who would be most likely to raise lots of small donations and get the big subsidies? Not fledgling candidates most strapped for funds, but incumbents and others who already well known or waging highly publicized fights for vacant seats. Spending reports on the 1976 House campaigns suggest that an average House incumbent could easily qualify for a $50,000 grant, while an average challenger might be able to match only $25,000 or so.

The plan would promote equity in some cases, but this aspect, too, has severe flaws. It would give candidates extra public aid if their opponents benefit from large independent outlays by interest groups, or decide to forego the subsidies and spend more than $150,000 in private funds. There are several things wrong with that. It makes the judgment that some kinds of constitutionally protected political activity - free spending by individuals and groups to promote their own candidates or views - are "excessive" or "bad." It assumes that government should impose that judgment and provide a financial counter-weight, instead of simply disclosing the spending and letting voters judge its desirabilty for themselves. Indeed, experience shows that lavish spending by rich candidates or well-heeled interest groups often becomes a campaign issue anyway - and does not necessarily bring victory at the polls.

On those two grounds alone, the plan deserved to be shelved. It may be possible to devise a modest program that would ease candidates' access to the marketplace without distorting political comptition in new, troubling ways. This wasn't it.