House GOP hardliners blocked debate on their party’s defense spending bill on Tuesday, making Pentagon funding the latest casualty of a civil war between Speaker Kevin McCarthy and his conservative critics.

Republican rebels blocked the annual defense appropriations bill in a procedural vote, delivering a stunning loss to McCarthy and hawks who’d sought to break an impasse over federal spending that forced leaders to yank the legislation last week.

House GOP lawmakers are still at odds over an upcoming spending confrontation with the Senate just 12 days out from a government shutdown. Many conservatives withheld their votes on the Pentagon bill to force Republican leaders to take a harder line on a stopgap to keep the lights on.

Ultimately the procedural vote on the $826 billion defense spending bill, known as a rule, failed in a 212-214 vote on Tuesday. Five Republicans defected on the procedural vote, which almost always falls along party lines.