THIS YEAR'S foreign-aid bill is now coming to a vote in the House of Representatives - and it could hardly have come at a worse time. The House leadership, perceiving the danger, has pulled the bill back several times. But with the end of the session drawing near, the calender forces it to go ahead despite the warning signals.

A passion to cut taxes has seized Congress. Since most of the congressmen are also getting highly sensitive about the federal deficit, they are looking for spending bills to cut as well. Most of the possibilities are not inviting. But there's always the foreign-aid bill.

True, it's already been sharply cut in the Appropriations Committee. Also true, this country is already in arrears in its promises to the international aid funds. But voting to cut the bill again is a quick and easy gesture against federal spending. Unfortunately, it's a gesture that threatens real harm to a lot of people around the world. Some of them are in this country - people whose jobs depend on the exports that economic aid and World Bank loans finance.Most of the beneficiaries are, of course, in other countries - countries a good deal less fortunate than this one.

The politics of foreign aid has become immensely more complicated, over the past year, because of President Carter's good-hearted but unfocused human-rights campaign. A number of congressmen are now trying to enact human-rights amendments in ways that threaten severe damage to foreign aid.

One-third of the money in this bill would go to the international lending operations - the World Bank and the regional funds for Latin America, Africa and Asia. They raise money from the rich countries and lend it to the poor ones to support economic development there. Those agencies are run by boards representing both the donor governments and the borrowers. The idea is to give the poor countries access to capital without forcing them to become political clients of the industrial nations' governments. But the House is going to take up a series of amendments designed, in one way or another, to impose American political standards on the World Bank's loans.

It is bad enough to require, by law, that American directors vote against loans to certain unpopular countries that, in the congressional view, violate their citizens' rights. It is bad because it sets a precedent of trying to use the World Bank as a lever to further one nation's political attitudes. That becomes an invitation to other nations to try the same thing. But some of the proposed amendments would take a drastic further step: prohibiting any part of the American contribution to the World Bank from being used, directly or indirectly, to help certain named countries like Vietnam. Other versions are explicitly protectionist, forbidding any aid to development projects that might compete with American products, like tropical palm oil that might be substituted for American soybean oil.

These amendments would attempt to transform the World Bank from a genuinely international and cooperative agency into an instrument of American policy. If any of the prohibitions is enacted in the final bill, the World Bank will refuse the entire contribution. If there is no American contribution, it is unlikely that other nations will continue to contribute.

The World Bank has been built, largely through American leadership, over many years and many Congresses. It would be a sorry commentary on the present Congress if it now jeopardized that valuable structure in a self-defeating campaign to attach political conditions to economic aid.