This has been the week when Ronald Reagan preached an East-West ideological crusade to a British Parliament deeply involved in a nonideological war.
The American President's audience in the Palace of Westminster was concerned with a world in which capitalist Argentina is taking military help from its best trading partner, the communist Soviet Union, in its battle for capitalistic British property in the South Atlantic.
And even while the President was speaking in London, capitalist Israelis were doing their best to obliterate Palestinians who are fighting not for Karl Marx or Moscow, but to regain a right to live in the lands in which they were born and where their ancestors have been living for thousands of years.
The world of today is full of contests among peoples which seem to arise out of almost anything but ideology. The case of Argentina is perhaps the most spectacular example in a long time of how ideologically fragmented today's world has become.
Who are Argentina's friends and suppliers in their war for the Falkland Islands?
The present regime in Argentina has been vigorous at home in its suppression of communism and has tolerated and abetted a campaign of anti-Semitism. Yet its main military suppliers have been the Soviet Union, Cuba, and Israel.
The explanation in the case of Argentina is largely trade. The Soviet Union takes 30 percent of all Argentine exports. This includes 75 percent of Argentine grain exports. Since July 1980 the Argentines have been under a contract to supply at least 4.5 million tons of grain annually to the Soviets. In April 1981 it signed another agreement to provide from 60,000 to 100,000 tons of boned beef.
Currently the Soviets are negotiating with Argentina over fishing rights and possible cooperative fishing operations in the Antarctic waters lying south of South America. Argentine fishing rights in this area would be substantially increased if Argentina were to obtain sovereign control over the Falkland Islands. In other words, Moscow has a potential industrial stake in an Argentine victory in the Falklands.
Then there is the ideological anomaly of Israel's role in the Argentine war. Israel has been selling weapons, including fighter aircraft, to the Argentines. It has agreed under pressure to refrain from signing any new contracts during the present war but has not agreed to suspend delivery under existing contracts.
Another possible reason for Israeli policy toward the Argentines is indicated by the fact that the neoconservative political movement in the US is both strongly pro-Israeli and pro-Argentine. This shows up in the fact that the controversial US chief delegate to the United Nations, Jeane Kirkpatrick, is a member of the neoconservative group and pursues a strong pro-Argentine and pro-Israeli policy at the UN.
Why would a vigorous supporter of Israel also be pro-Argentine?
The one plausible explanation is that Buenos Aires is using the argument of prior possession for its claim on the Falkland Islands. This is the basis for Israel's claim on the West Bank in Palestine, which the Israeli government calls Judea and Samaria. If Argentina is justified in using force to reclaim lands it once possessed, then Israel has the same justification for taking lands away from their recent occupiers, the Arabs.
National and tribal interests and expediency explain the association of the Soviet Union, Cuba, and Israel with Argentina's cause in the South Atlantic.
Similar reasons of expediency or national or tribal interests prevail in the war between Iran and Iraq. Moscow has in the past been the main supplier of weapons to Iraq, while the Iran of the Shah's era took its weapons from the US. Moscow is now tending to side with the passionately Islamic regime in Iran. It has apparently suspended selling arms to Iraq, which must get new weapons from the more conservative Arab countries, Saudi Arabia and Egypt. Meanwhile Israel has been selling spare parts to Iran for the latter's American weapons.
So here again we see expediency putting the Soviets and Israel momentarily on the same side in a regional war where the issue is partly territory and partly religion but not modern ideology. The Iran-Iraq war started when Iraq attempted to seize the far bank of the Shatt al Arab. This is the coastal end of the combined Tigris and Euphrates rivers. Success would have given Iraq control over the southern province of Iran, which includes the refineries and export center for Iran's oil industry.
Failure of the Iraqi invasion of Iran has had a reverse effect. Iraq's channel for exporting oil from Basra down the Shatt al Arab is now under Iranian guns. Also the defeat and weakening of Iraq has upset the whole Arab region. Israel has in effect been able to launch its long-expected invasion of Lebanon with its flank protected by the weakness of Iraq. The Arabs are too preoccupied with the implications of Iran's victory and Iraq's defeat to be able to take effective collective action in support of Lebanon and Syria.
Israel's southern frontier is now protected by its peace treaty with Egypt. Israel's access to American economic support and American weaponry is guaranteed by a pro-Israel slant in the attitude of the Reagan administration toward the issue. The State Department statement on the invasion said that ''the spiral of violence'' that triggered the invasion began with the ''assassination attempt against the Israeli ambassador in London.''
This version accepts the Israeli position and ignores the fact that there has been rising trouble along the Lebanon border since April 21 when an Israeli soldier was killed in southern Lebanon by a land mine. This was in an area controlled by Israelis. The Israelis ''retaliated'' within hours with major air strikes against PLO villages along the coast. That attack broke a nine-month truce between Israel and the Palestine Liberation Organization.
The White House announced that it would continue sending weapons to Israel. Plainly, the Reagan administration is not going to treat this Israeli invasion of Lebanon by the same standards it uses in the case of Argentina's invasion of the Falkland Islands. No punitive action against Israel is contemplated.
The British police investigating the attempt on the Israeli ambassador in London find no evidence of a PLO involvement. There apparently was contrary evidence.
There are many other areas of tension in the world due to nonideological reasons. Another example is China, an officially communist state, which is in a state of unresolved hostility with Vietnam, also officially communist. At present China enjoys easier relations with capitalist US than with communist USSR. Offhand I cannot think of any important world tension due strictly to ideological causes.
Mr. Reagan is not likely to find many converts to the ideological view of the world he presented to a bemused audience in the Palace of Westminster last week.
They applauded vigorously when he labeled Argentina's invasion of the Falkland Islands as ''armed aggression'' and said that ''it must not be allowed to succeed.'' That remark related to the world the members of the British Parliament know. Mostly they listened politely when he preached his crusade against Marxism-Leninism.