AS STATE LEGISLATURES go back into session, it's worth taking a glance at the constitutional amendment purporting to require a balanced budget and the constitutional convention that its advocates want called in order to consider it. The amendment itself has been on the political back burner since last summer, when it was replaced by Gramm-Rudman as a goad to deficit reduction. Yet 32 of the required 34 states have issued calls, in one form or another, for a second constitutional convention to pass it. The convention proposal was adopted nowhere in 1985, despite strenuous efforts in Michigan. But its advocates hope for action this year in New Jersey, where Republicans captured the Assembly last fall, and Kentucky.

What would happen if those states, or two others, passed such resolutions? No one knows. That uncertainty has been one major reason the convention proposal is stalled: almost any legislature is happy to pose as a backer of a balanced budget, but most legislators are understandably hesitant about actually setting a convention in motion. Sen. Orrin Hatch (R-Utah) has a bill that attempts to answer some of the questions the convention procedures raise; it was passed unanimously by the Senate Judiciary Committee. But once it gets past the first easy questions, it raises more doubts than it settles. It helps to confirm that the convention proc that it has great potential for mischief, that at best it is a diversion from the difficult policy problems Congress now faces.

Even on the easy questions Mr. Hatch's bill doesn't always get the right answers. It is arguably right to say that Congress, in determining whether 34 states have called for a convention for the same purpose, should require not identical language but similar purposes. It is sensible in setting a 7-year time limit on any state's call for a convention. A constitutional convention, like a constitutional amendment, should result only from a contemporaneous decision by 34 states. Unfortunately, the Hatch bill grandfathers in the calls for the balanced budget amendment convention, even though 18 of them were made more than seven years ago. Why? If these states want to renew their calls, fine. If not, they should be disregarded.

From there the going gets rougher. The Hatch bill would give states the number of seats in the convention they have in the Electoral College -- though that doesn't meet the one-person/one-vote standard. It purports to limit the subject matter of a convention. But would limits be effective if the convention delegates proposed other amendments and 38 state legislatures passed them? Those questions cannot be definitively answered until and unless a convention meets. Even a good-faith effort such as the Hatch bill cannot obscure what legislators have found out: a constitutional convention is dangerous and unnecessary.