...Even his aides wonder if he can meet lofty expectations, which have elevated him beyond a politician’s normal realm, thanks to his celebrity, ambition and biography. While a presidential campaign would highlight Mr. Obama’s strengths as a lyrical communicator and personable campaigner, it also could expose the shortcomings of a 45-year-old politician not fully developed, and one who will not enjoy the luxury of learning in obscurity. The next phase of his political development will inevitably draw intense and less flattering scrutiny, particularly if he goes head to head with Senator Hillary Rodham Clinton for the party’s presidential nomination; he...