Two Mideast wars are in full swing: one, the obvious, in Lebanon; and the other, for superpower influence once the guns are silent.
The Soviets have so far acted with relative restraint on the first front. They are accelerating activity on the second.
Having just received the traditionally pro-Western King of Jordan, Moscow is said by generally reliable sources to have invited the secretary-general of the Arab League for talks July 5. The diplomat, Tunisia's Chadli Klibi, has accepted , the sources report.
The Kremlin is clearly aware that both superpowers are likely to emerge losers, in various respects, from the fighting in Lebanon.
Yet the Soviet hope is that Arab rancor toward Washington over the Israeli invasion will benefit the Kremlin's longtime bid for a share of the Mideast diplomatic action.
Put differently, the Kremlin aim is credibly to challenge the Americans' near monopoly over the Arab-Israeli diplomatic arena, with the help of key Arab moderates like Jordan's King Hussein, President Hosni Mubarak in Egypt, and Saudi King Fahd.
''What Begin did (in invading Lebanon) will strengthen anti- American sentiment,'' a senior Soviet official said in a recent interview. ''For any Arab , what Israel does is a product of what America does. . . . Israel showed the helplessness of the Arab states, and people do not like to be shown helpless.''
The reception the Soviets give Mr. Klibi is likely to resemble that reportedly extended to King Hussein in talks with Premier Nikolai Tikhonov and Foreign Minister Andrei Gromyko: extremely polite, even bordering on deferential in its solicitation of moderate Arab thinking on future diplomatic prospects, and scathing in its criticism of an Israeli invasion deemed ''impossible without US support.''
The main problem for the Kremlin is to combat the impression that the Soviet Union, as much as the Arabs, has proven helpless to counter the Israelis.
The official Soviet news agency Tass reflected the extent of Soviet sensitivity on this issue when, breaking with precedent, it moved a dispatch late June 30 on the performance of Kremlin weaponry. The gist was that it would be ''deliberately false'' to suggest Syria's Soviet-made arms had proven inferior to the Israelis' US-manufactured weaponry.
The Soviets have been continuing a military airlift to Damascus, although it apparently remains a more limited effort than the resupply operation in the 1973 Mideast war.
At least as difficult for the Kremlin to counter will be the impression of ''helplessness'' on the diplomatic front. The flipside of Arab resentment over the Americans' huge commitment to Israel is the assumption that this patronage gives Washington more potential influence over the Israelis than Moscow can conceivably exert. Even as Israel's invasion has prompted Syria and the Palestinians to heap scorn on US policy, both parties have looked toward Washington for prospects of reining in the invasion force.
The Soviet hope is that Arab resentment will weigh most heavily in the post-invasion makeup of the Mideast. Soviet officials are realistic enough not to count on key Arab moderates suddenly becoming Kremlin allies, yet they seem to feel that countries such as Jordan, Egypt, and Saudi Arabia will move toward a more evenhanded strategy, in large part as a slap at Washington.
The corollary, reportedly endorsed in King Hussein's private comments to Soviet officials, is that a less overtly pro-American entente will emerge among key moderate regimes.