Bankruptcy lurks over a divided Common Market

After the failure of the two-day European Community summit here this week, Western Europe is down for the count. Because the 10 leaders boxed rather than settle the community's financial crisis, the Community faces bankruptcy by October.

Such a total knockout still can be averted, and may well be. But if the acriminous Brussels summit - which followed last December's disastrous Athens meeting - is a guide, Western Europe may be so battered when it gets up that its spirit may be fatally broken.

This prospect is dangerous for the United States.

A bickering, divided Europe weakens NATO and American security, diplomats here say.

''This is a setback for transatlantic relations,'' British Prime Minister Margaret Thatcher admitted after the summit broke up Tuesday. ''For the second time, Europe has not been able to sort out its own problems, largely because we are not able to face up to these problems.''

Mrs. Thatcher's pessimism was tempered a bit by knowledge that some progress had been made at the summit. For the first time, Western Europe seemed to be moving toward controlling spending, a formula reducing agricultural surpluses, and adding new taxes.

In the end, diplomats reveal that only $250 million prevented the summiteers from reaching an agreement on the crucial issue, a British rebate from the EC.

''We were not that far from agreement,'' Mrs. Thatcher noted. ''We'll just have to try one more time.''

But the fact that such a small monetary gap could not be bridged demonstrated the lack of confidence among the leaders. The British prime minister's tough stand infuriated her colleagues. ''Mrs. Thatcher inflamed a wild debate,'' German Chancellor Helmut Kohl said.

At one point, an exasperated French President Francois Mitterrand rebuked the British leader, declaring, ''I thought we had come here to make efforts.''

Despite almost 30 hours of intensive talks, this gap of mistrust could never be filled. To Mrs. Thatcher, her demands embodied a principle of correcting a budgetary imbalance: Why should Britain, as the Community's seventh poorest country per capita, pay more than all other members except West Germany to keep the Community solvent?

For the other countries, though, the British demands stemmed from greedy shortsightedness. They felt the British principle of budgetary imbalance had been met. From now on, a country's contribution would be tied to its wealth.

But the issue of a rebate remained. ''The British principle consists of saying, 'Give me my money,' '' a Mitterrand aide complained.

These difficulties paint a frightening picture of the Community's political weakness. When the Common Market was founded, the two biggest countries - Germany and France - could push, even shove, their smaller partners into agreement. But after Britain, Denmark, Ireland, and Greece entered during the l 970s, this power balance broke down. British interests had to be accounted for.

The prospect is difficult. Industrial Britain will not pay for France's farmers, and this structural difficulty left leaders in Brussels worried.

The next scheduled summit is in June at Fontainbleau.