Growing American anger over the level of allied support for the U.S. military effort in the Persian Gulf has sharply eroded public and congressional support for NATO, congressional observers and foreign policy experts said last week.

The gulf crisis erupted at a time when the end of the Cold War and the Soviet withdrawal from Europe already were chipping away at the North Atlantic Treaty Organization's reason for being.

The Bush administration has explored ideas for new missions for the alliance, even though it was assumed that U.S. financial and troop commitments would be scaled down.

Secretary of State James A. Baker III, in a speech last December in Berlin, said he saw resolving regional conflicts as part of NATO's "second mission" in a world where those conflicts would replace the Cold War struggle. Last week, a senior State Department official assured reporters after Baker met with NATO officials in Brussels that "you will see other allies providing {ground} forces" in the Middle East.

But despite pleas by Baker to send at least "token" ground forces to the region, until yesterday only Britain had agreed to commit a substantial number of troops. Yesterday, however, French President Francois Mitterrand, angered that Iraqi troops entered the French Embassy in Kuwait and detained diplomats, said he would dispatch up to 4,000 troops to the region. And West German Chancellor Helmut Kohl announced a $2 billion gulf package, of which about half is transportation and financial aid to the United States.

Despite these recent moves, however, the gulf crisis, one foreign policy expert said, shows that "NATO is going to be increasingly irrelevant in the new world order -- or disorder." In a book to be published next year, Stephen F. Szabo, an assistant dean at Johns Hopkins University's School of Advanced International Studies, said, "Those, especially in the United States, who looked to the gulf crisis of 1990 as the beginning of a new role for NATO and a means for solving the alliance's post-Cold War identity crisis . . . are likely to be disappointed."

Congressional anger with the allied effort erupted last week in unusually bitter, and bipartisan, attacks in the House against Germany and Japan, in particular, for not contributing enough. The House overwhelmingly voted to begin withdrawing troops from Japan unless that country pays the full cost of the U.S. military presence.

The move is expected to go nowhere, congressional sources said, but the sentiment behind it may linger even if U.S. allies increase commitments in the gulf.

"When the defense appropropriations bill comes to the floor," one key Senate aide predicted, "the NATO alliance will come up sucking sand."

"There was no role for NATO" in the crisis, another Senate aide said. "It couldn't play a part as a unified command structure and there wasn't much it could do. This, in fact, may be a real turning point."

Sen. Jeff Bingaman (D-N.M.), a member of the Armed Services Committee, said, "This situation in the Middle East is one of those incidents that people are going to look at to see how useful {NATO} is in dealing with real-life problems that we are going to face in the next decades. Unfortunately, it hasn't proven that useful."

Increased financial contributions by the allies may help repair the political repercussions shown by the House vote, he said, "but clearly the reluctance of our allies to step forward absent much haranguing is troublesome."

Other congressional observers and foreign policy experts, while acknowledging some strains on the alliance as a result of the gulf crisis, said the political fallout may turn out to be little more than short-lived posturing.

Sen. Richard G. Lugar (R-Ind.), a member of the Foreign Relations Committee, called the House debate "unfortunate." Lugar said it was an attempt by some legislators to "criticize the president obliquely" while saying they supported his policy.

"Certain members of the House and Senate found that on the hustings this ally-bashing had a certain resonance," Lugar said. "But this does not portend the beginning of the end of a mission for NATO. A degree of the ally-bashing is playing on a certain degree of uneasiness on how this may play itself out," he said.

Gregory F. Treverton, a senior fellow at the Council on Foreign Relations in New York, said, "NATO is finding it difficult to adjust to changing circumstances," but it was "always hard to know whether the {congressional} reaction is noise or real."

"This is not the first time that the United States has been unhappy with our European allies' actions in response to U.S. moves in the Mideast," he said. "We've complained before that the allies have not been forthcoming or helpful," he said, recalling European resistance to sanctions against Libya, France's denial of overflight rights to U.S. planes that bombed Libya in 1986 and that except for Portugal, "everyone, including Britain . . . denied the use of facilities and transshipment rights to resupply Israel" during the Arab-Israeli war in 1973.

Each time "there has been this undertone in Congress," he said, "that we will retaliate" and cut aid to Europe, but nothing happened. On the other hand, he said, the collapse of the Soviet Union and the likely reduction in U.S. forces in Europe may enable Congress this time to vent its displeasure in practical terms.

Six West European diplomats interviewed last week insisted that the alliance countries had made substantial contributions to the effort -- in logistical support, naval forces and materiel. The U.S. buildup in the gulf would have been impossible without such allied assistance, they said. In addition, NATO has held two full ministerial meetings and daily coordinating sessions on the crisis, something the diplomats said was "unprecedented" for an out-of-region situation.

A Belgian diplomat acknowledged, however, that many of the allies would have trouble sending ground forces because of public resistance. A U.N.-sanctioned force, he said, would increase Belgian public support "and make it easier for governments like mine" to send such forces. The Soviet Union has also indicated it might dispatch ground forces under a U.N. banner.

The diplomats said they understood that U.S. resentment may increase if fighting breaks out and U.S. troops bear the brunt of the casualties.

A West German diplomat said an American told him that the U.S. public believes "it is important that {in the event of war} some of the body bags coming back be European." But the diplomat said that barring a change in the West German constitution, no ground forces are likely to be sent.