The next 10 weeks or so are the make-or-break period for President Barack Obama's second term and his broader legacy, experts say. Only by securing speedy Senate victories on landmark issues such as immigration and gun control can the president leave himself enough time for a potentially bruising and protracted fight in the GOP-controlled House. "You have a president who's willing to compromise; you have public opinion that's been marshaled," says one senior White House official. "The question is, 'Can Congress function?' And we'll have to see."