Congress is poised for an epic failure in its efforts to combat Zika before lawmakers leave Washington for a seven-week vacation - and it could come back to bite Republicans at the ballot box if there's an outbreak of the mosquito-borne virus in the United States this summer. 

Senate Democrats are expected to reject a GOP funding measure on Tuesday, according to senators and aides, arguing that it would rob Obamacare of funding, impose new restrictions on Planned Parenthood and provide some $800 million less than the Obama administration is seeking. They're also miffed that the measure, part of legislation to finance the Veterans Affairs Department, would allow the Confederate flag to fly at veterans cemeteries.