The withdrawal of the bid by Dubai Ports World occurred not because the foreign investment committee rejected it but because of a torrent of criticism from Capitol Hill, around the same time that similar criticism of a deal by the Chinese state energy company to buy Unocal also led China to withdraw.

Meanwhile, the problems of the 3Com deal are sure to aggravate tensions with China.

This month, federal officials charged a Defense Department official with passing classified documents to China. In a separate case, the Justice Department arrested a former Boeing engineer in California on charges of economic espionage for the Chinese.

The Treasury Department adamantly opposes extending the curbs on foreign investments into areas that affect economic security as opposed to national security, though it says it will monitor growing foreign investments in whole sectors of the economy, even in the financial sector.