The Hon. Thomas P. O'Neill Jr. last week admitted that he has no ideas. In a meeting of the Democratic Caucus, usual thoughts were expressed. The bond market had swooned. The stock market was in calamitous decline. Inflation was in the area of 20 percent, and the prime rate was at a historic high. Sen. Henry Jackson said that ""we are on the verge of financial crisis if we're not already in it." All Washington resounded with talk of balancing the budget by cutting spending in fiscal 1981. Yet the Hon. O'Neill stomped his feet and declared his opposition: to balance the budget would be "to dismantle the programs I've been working for as an old liberal."

Aram Bakshian, in his highly readable new compendium of campaign lore ("The Candidate,"" 1980), describes Speaker O'Neill as Falstaffian. Last week, Speaker O'Neill outdid Falstaff in bathos and in bluster. Would all old liberals continue the spending spree with the inflation rate soaring near 20 percent? Would Lord Keynes? Harry Johnson, the renowned economist, argued convincingly that Lord Keynes would not, nor did Keynes approve of endless deficits. Yet perhaps Speaker O'Neill does not consider the eponym of Keynesian economists an old liberal. What of Walter Heller, chief economist under both Presidents Kennedy and Johnson? Last week Heller called for reduction not only in spending but also in taxes.

Speaker O'Neill insisted last week that inflation was caused mainly by high energy prices. He would be more interesting if he had said that inflation was caused by the artifices of 12 fat bankers holed up in the Alps. By now, everyone capable of reading a newspaper must know that Germany France and Japan -- to name but three -- pay higher energy prices than the United States and have far lower inflation rates. If high energy prices were the cause of inflation, our inflation would be comparatively mild.

Last week the Lion of the Lower Chamber hoped aloud that the Democratic Party would not turn away from its tradition of assistance to the poor, the aged and the sick.

Both parties ought to have a tradition of assistance to the poor, the aged and the sick. Yet if inflation continues, these parties will have a lot more people to assist. Government policies are presently impoverishing the middle class at the rate of nearly 20 percent per year. The dollar that a working man earned in 1967 is today worth 44 cents. Throughout the 1970s, Speaker O'Neill's constituents realized hardly any increase in real income. The government prospered while the working man suspported it with more and more of his income.

Nevertheless, Speaker O'Neill plods on, an old liberal, victimized by Arabs but devoted to the poor, the aged and the sick. If he gets his way, we shall all be poor, aged and sick.