Despite the hopeful words of the economic summit communique', the world's leaders took no new or significant action to deal with the critical Third World debt problem, beyond a routine endorsement of the now-famous "Baker initiative'' announced last October.

Prior to the summit, Uruguayan President Julio Maria Sanguinetti wrote host Yasuhiro Nakasone on behalf of the Cartagena group of debtor nations. He labeled the Baker plan "insufficient" and appealed, without success, for lower interest rates.

sk,2 Given the history of economic summitry, it is not too surprising that the really tough problems get swept under the rug. And the Tokyo summit was overwhelmed by the Soviet nuclear explosion and the terrorism issue.

But whatever the limits of summitry, the debt problem remains a real one. As Sen. Bill Bradley (D-N.J.) has observed, the Baker debt initiative was a significant step because it recognized that the administration's earlier approach to the problem, stressing austerity rather than economic growth, had "reached a dead end."

But the Baker plan is not broad enough in scope, and too demanding on the 15 debtor nations involved: It insists that they make drastic changes in their economies so as to become more "market-oriented" and "growth-oriented." If that "privatization" test is met, Baker proposed an injection of just under $10 billion a year in new capital in the 15 nations (over and above what had been planned) for the next three years, from commercial banks and international organizations such as the World Bank.

The critical problem the Baker plan fails to address is that the developing countries have been forced to become large net exporters of capital to the industrial nations. What the Third World needs is relief from this burden.

Since the debt crisis broke onto the world's consciousness in 1982 when Mexico couldn't pay interest on its debt, these interest payments have been "rescheduled," -- that is, added onto the total debt owed. In banker Felix Rohatyn's apt phrase, "This device is a bridge to nowhere." Despite great effort to boost exports and reduce imports, the total debt has continued to expand.

The Catch-22 is that if relief is provided by cutting interest rates and stretching out the terms, many American banks will have to adjust their books to reality and accept damaging losses. Rohatyn and Bradley approach the problem somewhat differently, but both call for dramatic changes in the Baker plan.

Rohatyn wants to cut current interest rates to Latin American countries by four percentage points, saving them about $15 billion annually. That would cut the profits of American banks, he figures, by $4.5 billion.

To compensate, he proposes a guarantee of the banks' loans by either the United States or the World Bank. In effect, "the banks would exchange current profits for long-term financial security." And to add new capital, Rohatyn would put the bite on Japan -- which is running huge international trade surpluses -- for $100 billion over five years, funneled through the World Bank and the Inter-American Development Bank.

Thus, together with $75 billion in interest-rate relief, Rohatyn is talking of the injection of an aid package of $175 billion of new capital -- $35 billion annually against Baker's $10 billion.

Bradley emphasizes relief from the existing debt, more than new loans, for countries that initiate their own programs to "rekindle growth and nurture democratic institutions." A critical test would be the ability of the Third World nations to stop the existing, devastating flight of capital out of their countries to safer havens.

If the citizens of the developing nations plainly believe their own countries are a lousy risk, why should foreigners continue to pump new money in? Bradley is convinced that his plan would encourage real economic reform from within the affected countries, because it would not be dictated from the outside. If the Baker initiative has stalled, it can be attributed to the political inability of most debtor nations to admit that they're knuckling under to Uncle Sam and the big bankers.

To heads of state and industrial nations' finance ministers, ideas such as Rohatyn's and Bradley's appear to be off the wall. But as Rohatyn says, the banks have already become prisoners of their big borrowers. Peru and Nigeria have taken the situation in their own hands, and placed a "cap" on their interest payments. Mexico, a neighbor and partner of the United States, all agree, is a special case. A collapse there could have untold consequences.