WASHINGTON - While politicians decry negative advertising and personal attacks, the bottom line is that such tactics often work. People may not quite recall the specific controversy, but negative campaigning can still raise a question mark in voters' minds about a candidate and prove hard to overcome. Attack campaigns, such as those by outside groups in the current presidential campaign, "are bad for the system," President Bush (news - web sites) said on Monday, including a television commercial questioning rival John Kerry (news - web sites)'s military service in Vietnam. No matter that Kerry and his supporters have claimed the...