RESTON, VA -- Foreign defense companies looking to acquire a U.S. defense contractor may be required to submit a written notice of such an acquisition if the Bush administration decides to change current policy, a senior Defense Department official said yesterday. Section 721 of the Defense Production Act of 1950, also known as the Exon-Florio provision enacted in 1988, authorizes the president to suspend or prohibit any foreign acquisition, merger, or takeover of a U.S. corporation that is determined to...