Is there less than meets the eye in Treasury Secretary James A. Baker III's new Third World loan strategy? At least so far, it appears strong on rhetoric, but short on action.

Baker has been widely praised here and abroad for shelving some of the Reagan administration's first-term economic ideology and turning, instead, to pragmatic solutions. On the debt issue, he has conceded that it makes no sense to drive Latin American borrowers into even deeper recession. If they have no reasonable hope of emerging from enforced austerity, Baker wisely concluded, some of them could default or face revolution, with horrendous consequences for the international financial system.

It was high time to acknowledge that the former patch-it-together, muddle-through strategy -- with the International Monetary Fund in the reluctant role of Scrooge -- wasn't working.

Lame-duck World Bank President A. W. (Tom) Clausen admitted Monday in Buenos Aires that the rich nations had "underestimated the degree of suffering" that would result. In a speech loaded with promises of a "quantum leap" in loans in a "new era" of cooperation, there was an implied mea culpa on behalf of the industrial world's financial establishment.

But Baker's new strategy calling for a 2.5 percent annual increase in commercial bank loans also may be undershooting the need. Baker made two key decisions soon after moving into the Treasury job early this year: first, that the United States would have to play a more active role in getting the big Latin debtors out of hock or those markets might be lost forever to American exporters; and, second, that at an appropriate time, the United States, Japan and West Germany (along with any other nation that would cooperate) had to move against the overvalued dollar.

The latter came first, on Sept. 22, when the Group of Five nations -- France and Britain joining the Big Three -- agreed on a program of intervention to bring the dollar down. This program, which has been highly successful so far, has deflected protectionist sentiment in Congress.

Then, at the annual meeting of the IMF and World Bank in Seoul, Baker outlined a three-part program calling for a $20 billion increase in loans by commercial banks to 15 major debtors over the next three years, a boost of $9 billion in World Bank and other multilateral development bank loans over the same period and economic reforms by the borrowing countries -- all designed to encourage resumed economic growth.

This was a big switch in policy direction. In an interview just before the Seoul session, Deputy Treasury Secretary Richard Darman explained the need to generate light at the end of the tunnel. Unless creditor nations can arrange "some supplementary program that can begin to provide hope of long-term growth, there's a risk of just ever-expanding but perpetually hopeless short-term programs" in the Third World countries, Darman said.

The big question is whether the Baker program is bold enough to do the job. The $20 billion additional lending by the commercial banks seems minuscule against the $10 billion that Mexico alone says it will need.

One view, outlined by Carol Loomis in the Dec. 23 issue of Fortune magazine, is that the Baker plan won't work because the debtors already owe too much. The only solution, according to this view, is to lighten the debt burden by having the banks write down some of the $350 billion owed by Latin America. That means big losses for the banks.

But according to Wall Street-wise John Heimann, former comptroller of the currency, the Baker plan already implies a substantial amount of loan write-offs by the banks over the next five years or so, with the only question being how much. There will be more write-offs, he says, if there's a global recession, less if there's a recovery. Privately, World Bank officials say that this is a correct interpretation.

Heimann (now vice chairman of Merrill Lynch Capital Markets) predicts that, after "some kicking and screaming," the banks, including European banks now giving Baker the cold shoulder, will fall in line with Baker's plan because they have no other option.

Interestingly enough, the foreign banks have a bigger stake in Latin America than do the American banks. U.S. banks had claims of only $77 billion out of a total of about $220 billion in six key countries: $8 billion out of $26 billion in Argentina, $24 billion out of $76 billion in Brazil, $6.5 billion out of $13.5 billion in Chile, $26 billion out of $73 billion in Mexico, $2 billion out of $6 billion in Peru and $10.5 billion out of $26 billion in Venezuela.

The foreign banks may have more adequate loan reserves than the American banks, and Latin America -- as some of the Europeans stress -- is in the United States' sphere of influence. But their commitments are very heavy, and the Europeans, Japanese and others can't duck their share of responsibility for the success or failure of the new initiative.

Having taken the lead, Baker now must show that the United States means business, and is not merely trying to buy time in which the second Reagan administration can escape responsibility for the present phase of the debt crisis. In Seoul, Baker strongly implied future support for a big capital increase for the World Bank. But it makes no sense to be trying to breathe new life into the World Bank, unless the administration makes clear that it will expend some of its political capital to expand the banks' lending power.

Besides, a capital increase does not place a drain of any kind on the federal budget. Bank treasurer Eugene Rotberg pointed out in Seoul that in the 38 years following its initial paid-in capital of $635 million, the United States has paid a mere $500 million of additional capital to the bank. (But expansion of the bank's capital, most of which is subject to call and is never transferred to the bank, gives the bank legal authority to borrow in private markets.)

And let's not forget Africa, so far ignored with other small debtor nations. Baker has to go back and fight for the part of his proposal relating to new help for Africa that he was forced to withdraw at the last moment in Seoul.

The bottom line is that Third World debt is growing faster than earnings from debtor countries' exports and will continue to do so, even if the Baker plan as it now stands is implemented. The debt total is not, in any sense, manageable. Some large part of it must be written off. Inevitably, if the banks -- American and foreign -- don't do this in some logical fashion, it will be done for them by the borrowers.