US Senate Democrats block $1.15 trillion defense bill over Iran war objections

This year's NDAA authorizes an unprecedented $1.15 trillion for defense, determining everything from how many ships, aircraft and missile systems are bought to pay raises for the troops and how to address geopolitical threats.

Historically seen by both parties as "must-pass legislation," the NDAA is one of the few major bills that always passes, having become law annually for more than six decades.

Despite the setback, it is early in the NDAA process. Each year, the House of Representatives and Senate pass their own versions of the NDAA, before Armed Services committee negotiators reach a compromise version that then comes up for a vote in each chamber.

If the compromise version passes, it would be sent to the White House for President Donald Trump to sign into law or veto.