President Barack Obama said on Sunday that he doesn't intend to become his successor's constant critic - but reserved the right to speak out if President-elect Donald Trump or his policies breach certain "values or ideals."....... He heaped praise on former President George W Bush, saying he "could not have been more gracious to me when I came in" and said he wanted to give Mr Trump the same chance to pursue his agenda "without somebody popping off" at every turn. But Mr Obama suggested there may be limits to his silence.