The Senate on Thursday night sent its $59 billion war funding bill back to the House without approving more than $20 billion in domestic spending tacked onto the lower chamber's version.
The House had added money for teachers, Pell grants, a summer-jobs program and border security to the supplemental passed by the Senate in May.
The House bill didn't even clear a simple majority in the Senate on a 46-51 vote.
The Pentagon has been “seriously planning” for the possibility that Congress will not pass emergency war funding before lawmakers head to the August recess.
The House can pass the Senate bill in their last week before lawmakers leave for the summer break.
The House version of the supplemental appropriations bill, with the billions of dollars in additional domestic spending, passed July 1 by 239-182, with 15 Democrats and 167 of 177 Republicans voting against the measure.
The amended version of the Senate's original bill drew a veto threat from the White House when $15 billion in education aid added by the House was to be partially offset by $800 million in cuts to new education programs.