On the eve of their second debate, President Obama and challenger Mitt Romney remain locked in a virtual dead heat nationally, with Republicans showing increased enthusiasm for their nominee after his big win in the first debate, according to a new Washington Post-ABC News poll. Likely voters in the new poll split 49 percent for Obama to 46 percent for Romney, basically unmoved from the poll two weeks ago, just before the two candidates met in Denver for their first debate. On topic after topic, the survey portrays an electorate that remains deeply divided along partisan lines and locked in...