JIMMY CARTER can fairly be blamed for the force behind the unholy alliance that threatens to tie up American participation in the international development agencies. For without his early rhetoric and lack of restraint, it is doubtful that such strong support would have been mustered behind the Harkin amendment, which requires the United States to oppose World Bank and other loans to countries engaging in "a consistent pattern of gross violations of internationally recognized human rights." This amendment swept the House and, though its prospects are less promising in the Senate, at the very least a rough struggle between the two chambers is in store when the legislation goes to a conference committee to iron out differences. It is backed, as we say, by an unholy alliance: pro-aid liberals waving high the early Carter banner of muscular public virtue, and anti-aid conservatives figuring to sink development aid under an unbearable load of human rights.

Mr. Carter himself, in just a few months, has gone through something of a sobering process. He no longer seems as certain that the United States has the reach, through its patronage and its preachments, to bring recalcitrant human-rights violators smartly to heel. He is prepared to accept certain limitations in the name of discretion and effectiveness, notwithstanding charges that he is "selling out." We find the change becoming; it suggests not surrender but maturity. In respect to funding for the international development agencies, his new attitude takes the form of support for the Reuss and Humphrey amendments, which simply call upon the United States to use its voice and vote to "advance the cause of human rights" by seeking, among other things, to channel assistance away from violators. That means the government would be required by law to heed human-rights issue but would not be locked into any single way of doing so.

The mandatory cutoffs required by the Harkin approach would indeed punish accused violators and let the United States symbolically hold itself aloof from them. But it would, in our view, deny the government the bargaining capacity it actually needs to improve human-rights conditions in countries applying for loans. Nor would it permit the government adequate political flexibility. Mr. Harkin notes that, say, practices torture, as long as the aid "directly" serves the people's "basic human needs." But this makes a mockery of the amendment's human-rights purpose, particularly when you crank in the difficulty of attaining international agreement on what sort of loans do serve "basic needs" and what sort don't. In fact, the Harkin amendment has already been tested; for a year it has controlled American policy in the Inter-American Development Bank. In practice, its automatic nature has left the United States isolated within the bank and open to the charge that, in compelling a negative vote on other than economic grounds, the United States is itself violating the bank's charter.

Diplomatic jawboning, which is what the Reuss amendment pretty much comes down to, has its limitations. Very scared or very stupid governments may turn away; it may not work at an adequate pace or depth. Certainly it won't be trusted by legislators who still think it terms of needing a club to use against an administration like the last one, which was often disclined to expend its diplomatic capital on human-rights issues. Practiced by an administration with a more credible commitment to rights, however, jawboning by American diplomats and American officers in the international banks has a potential that has yet to be tapped. The Carter administration deserves the opportunity of a fair test.