Foreign aid is having its usual rough ride through Congress and for the second year in a row will be funded by a stopgap continuing resolution rather than a more flexible regular appropriation bill.

Ever since the aid program began after World War II, Congress has insisted on reauthorizing it annually and these votes to extend it usually have been cliffhangers. This is because, although much of the money is spent in the United States, the program bears the label of "foreign giveaway" and has a limited political constituency.

This year the foreign aid authorization bill moved through House and Senate fairly early but then sat for several months in a conference committee. The bill was held up for various reasons, including the fact that Congress was in recess much of the summer because of the two presidential nominating conventions. There was also jockeying over a provision governing disclosure to Congress of covert intelligence activities.

Finally, with elections out of the way, the conferees sat down last week and quickly agreed on a $5 billion aid bill for the fiscal year that began Oct. 1. The bill, which Congress is expected to approve next week before quitting for the year, sets foreign aid policy and spending ceilings.The money is provided in separate legislation.

The authorization bill is not really needed to keep the aid program operating. It will be kept alive by a continuing resolution funding agencies whose appropriations bills are not enacted this year. But the authorizing bill contains several policy provisions, such as authority for the president to give military aid to nations excluded by law from the program, if he finds it to be in the national security interest.

But even while pushing the authorizing bill, House leaders decided against taking up the regular foreign aid appropriation bill for fear of being caught in another difficult fight over banning aid to certain countries and putting conditions on use of U.S. aid by international lending institutions.

House leaders also scrubbed for the year a bill authorizing more U.S. aid to the International Development Association which makes development loans to the poorest nations. This program has even less of a political constituency than the bilateral aid program and the measure was threatened with restrictive amendments if taken up by the House. Democratic leaders decided to let the Reagan administration deal with the IDA problem.