IF MEMBERS of Congress really believe they must have a legislative veto over the rules issued by regulatory agencies, the version approved last week by the Senate Government Affairs Committee is the best available. But that's not saying a lot, and before Congress edges any closer to enacting a general veto provision, it should do a little hard thinking about the kind of institution it wants to be.

Any legislative veto, if it is more than an empty gesture, would increase the power and, perhaps, the size of the already powerful congressional bureaucracy. Any veto would double the lobbying efforts on Capitol Hill of every organization that had lost -- or that thought it was going to lose -- a proceeding before any agency. Any veto would put Congress back square in the middle of the mess it was in before the regulatory agencies were established: swamped with details it had neither the special information or the time to handle.

The proposal approved by the Senate committee tries to minimize these problems by restricting the veto to new rules with an economic impact on business of more than $100 million and exempting all actions of the IRS and the departments of State and Defense. But that still leaves far more rules open to congressional review each year than any member could hope to master.

Under the Senate proposal, each committee with jurisdiction over an agency would be able to suspend any major new rule for 60 days. The rule would be vetoed if during that time both houses passed and the president signed a resolution of disapproval.

On the surface, this does not seem a bad idea. Congress can already override an agency's rules this way, and all the proposal adds is a formal review procedure and the power of a committee to suspend a rule.

But in practice, it would be something else -- and something pretty bad. The committee that oversees an agency would need a staff to advise its members on the wisdom of that agency's new rules. This staff, inevitably, would become a small version of the agency. Most likely, the agency would in time begin to negotiate with the staff in advance on the details of its rules. With this development of relationships, the whole idea of independent regulatory agencies with strong-minded officials who bring expertise and experience to bear on technical problems would begin to go down the drain.

Maybe that is what members of Congress, caught up in the wave of anti-regulatory sentiment, really want. But have they thought about the real-life consequences? This turn of events would make their jobs more complex and more time-consuming than they are now, and it would certainly make the august members themselves more vulnerable politically.

The way Congress has treated -- or, better, mistreated -- the Federal Trade Commission during the past year has sent a message that should cause the regulators to start hacking away at unnecessary rules. If it doesn't, Congress could always come back to the legislative veto at at a later date and try it out on a single agency, one that has a record of regulatory extravagance and excess. The idea of the legislative veto is so radical a departure from established practice that it would be terribly foolish to put it in place across the entire span of government now.