president biden just hours away from addressing the u.n. general assembly as tensions in his own party threaten to derail his agenda. the house speaker nancy pelosi says the next 48 hours will be critical. plus pfizer announcing a lower dose of its covid vaccine is safe and effective for kids ages 5 to 11. dr. anthony fauci telling cnn a decision from the fda could come within weeks. and we're learning about a 911 call reporting a so-called domestic dispute between gabby petito and her fiance, brian laundrie, just days before her disappearance. this as the fbi confirms it just concluded a search at the laundrie family home. i want to bring in now cnn white house correspondent john harwood and former obama campaign manager jim messina.