Trump said he vetoed the annual National Defense Authorization Act, or NDAA, because it "fails to include critical national security measures, includes provisions that fail to respect our veterans and our military's history, and contradicts efforts by my Administration to put America first in our national security and foreign policy actions."
"It is a 'gift' to China and Russia," he said in a message to the House of Representatives.
Although his previous eight vetoes were all upheld thanks to support from Trump's fellow Republicans in Congress, advisers said this one looked likely to be overridden, just weeks before he leaves office on Jan. 20.