IF YOU ARE among those who are fascinated with the fact that the same Reagan administration and Congress that express so much enthusiasm for the constitutional amendment purporting to require a balanced budget have not been able to submit or pass anything close to a balanced budget this year, then you may enjoy watching the progress of an amendment proposed by Rep. David Obey (D- Wis.). Mr. Obey is not one of those congressmen who think all things should be subordinated to the goal of a balanced budget; in fact, he is one of those Democrats the Reagan administration likes to attack as big spenders. In response, Mr. Obey is unkind enough to take the budget-cutters at their word. He will, he has announced, offer what he calls a "put up or shut up" amendment to every appropriation bill for fiscal year 1983, to cut total funds in that bill by the hefty figure of 31 percent.

The 31 percent figure, as you may have guessed, is the proportion that would have to be cut from each appropriation bill in order to reduce federal outlays to eliminate the likely deficit for fiscal year 1983. "If members want to have a balanced budget each year, regardless of economic circumstances, and they are not willing to raise taxes any further," he says, with ineluctable logic, "then they have no choice but to cut all appropriation bills by 31 percent."

Of course Mr. Obey knows his 31 percent bills aren't going to pass, and he knows -- and revels in the fact -- that most of those who say they support the balanced budget constitutional amendment will not vote for his measure. He is, as members of the party out of power are wont to do, having fun pointing up the gap between the in party's rhetoric and its performance.

But he does something else that is very useful, and that is to point out just how large that gap is. No serious practical person is proposing to cut federal appropriations 31 percent. The voters obviously do not want -- will not permit -- cuts of this magnitude. The democratic process is demonstrably failing to respond as some of Mr. Reagan's advisers thought it would: that is, the cuts in taxes on which they insisted have not forced Congress to cut spending by corresponding amounts. When Mr. Reagan himself dares not submit a budget that can promise to be balanced even years hence, we can be pretty sure that the amount of spending cuts the tax cut can force has already been realized. The constitutional amendment is a diversion, an attempt to keep people from recalling that this administration and its allies in Congress have come nowhere near delivering the balanced budget they promised. House members who support the constitutional amendment but refuse to support Mr. Obey's 31 percent amendments can justifiably be held up to ridicule.