The optics in the run-up to the midterms are startling: A two-term Democratic president is being treated like an outcast by his own party while his would-be Democratic successor is being treated like a rock star as she traverses the country on behalf of Democratic candidates.A beleaguered President Obama, buffeted by criticism of his handling of everything from ISIS to Ebola and stuck with an approval rating in the low 40s, is living the curse of a second-term president.