BATON ROUGE, La. -- Bill Cassidy, the Republican challenger to Sen. Mary Landrieu (D-La.), suggested during a debate Wednesday that residents of a desperately poor Louisiana parish could retire early to enjoy their Social Security benefits, even if the eligibility age rises. Cassidy, a congressman leading Landrieu in polls ahead of a likely runoff election, was hammered during their final debate on the traditional Democratic issue of Social Security.