YOU WILL NOT be stunned to hear that a lot of members of Congress this year are falling over their feet to endorse slashes in federal spending while leaning over backwards to avoid any reductions close to home That's no mean gymnastic feat in itself. But the real contortionists -- the most supple among the membership -- are performing an exercise that requires keeping a firm hold on a balanced budget while reaching out for more projects and aid -- costing more money -- for their own constituents. What should get slashed, they say, is all the wasteful spending in other districts -- or, better yet, the bureaucratic excesses that they see everywhere in general and nowhere in particular.

The House went through a classic bit of posturing the other day when it refused to raise the federal debt ceiling. Debt-increase bills always give economyminded congressmen a chance to vote against more borrowing without having to specify what spending they would stop. This time around, the House Republicans came up with a new angle by trying to trade a one-time increase in the limit for a House commitment to balancing the budget -- again, without spelling out where cuts would fall. All this earnest economizing no doubt sounds swell at home. What made it more than somewhat fraudulent was the fact that so many representatives assumed from the start that the debt-ceiling increases would first be voted down, then lifted later before any real damage is done.

Whatever you call it -- wishful, disingenuous or cynical -- the penchant for having it both ways is not a frailty confined to politicians. Consider the constituent survey that Rep. Morris K. Udall (D-Ariz.) completed recently. Instead of just asking voters what broad types of spending they wanted to raise or cut, Mr. UDALL TRIED TO BRING THE BUDGET CHOICES DOWN TO EARTH. @HE NOTED, FOR INSTANCE, THAT A CUT IN DEFENSE SPENDING MIGHT HURT RETIREES' BENEFITS OR Arizona bases, and that cutbacks in educational aid could curtail students' opportunities or cause local tax increases. In short, he asked his constituents to weigh the problems much as members of Congress do when serious voting starts.

The results were noteworthy for their inconsistencies. Over 61 percent favored a balanced budget this year, against 36 percent who endorsed President Carter's approach. But there was no broad agreement about where $30 billion should be cut. The largest vote, a bare majority, was for reducing aid to education. Over 40 percent favored trimming defense spending and outlays for veterans and leaving aid for agriculture, health and law enforcement the same.

All in all, Mr. Udall's constituents came out sounding much like members of Congress -- tired of deficits and inflation but torn about what to do. We suspect most representatives are finding similar sentiments at home. That may be one more reason why so many of them are taking every opportunity to cast easy votes or embrace generalities right now. They know they are going to have to make some tough and not-too-popular decisions all too soon.