As bad as the national polls are for George Bush and Bill Clinton, state-by-state surveys reveal even worse woes. In Michigan, for example, a Detroit News poll shows Clinton trailing independent Ross Perot 29% to 39% among what should be one of the Democrat's bedrock constituencies, union households. Bush gets 22%. And in a further sign that both major-party candidates are in trouble with their electoral base, only 47% of those who voted for Bush in 1988 say they favor him this year. Clinton fares little better, getting just over half of the 1988 supporters of Michael S. Dukakis. Things are even worse elsewhere. For example, in solidly Republican Nebraska, an Omaha World-Herald poll shows Bush and Perot tied at 36%. Clinton, with just 11%, is in fourth place, behind "undecided" at 17%.