'We understand her decision' -WH on Sinema becoming an independent

STORY: Sinema's decision Friday came just days after Democrats won a Senate race in Georgia and secured 51 seats in the 100-member chamber riven by deep political divisions.

Democratic President Joe Biden's agenda in the second half of his term was already clouded by Republicans set to take control of the House of Representatives on Jan. 3.

With their strong conservative bent, House Republicans already have put Biden on notice they will seek deep domestic spending cuts and tougher border security steps. It will be up to Senate Democrats to foil Republican initiatives.