President Trump issued a veto of the massive $740 billion defense bill known as the National Defense Authorization Act, shortly before leaving for a Christmas vacation in Florida.
Calling it a "gift" to Russia and China, the president's veto broke with the Republican-led Senate.
"Unfortunately, the Act 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," Trump explained in a statement accompanying the veto.
Both Speaker of the House Nancy Pelosi and Senate Majority Leader Mitch McConnell have said that their two respective branches will vote to override the president's veto once they return from their Christmas break.
While many Democrats took the opportunity to blast Trump for leaving the country vulnerable and jeopardizing the pay of U.S. soldiers, most Republicans took a more muted tone, with some even supporting Trump's position.
Others, like Armed Services Chairman Sen. James Inhofe (R-OK) and Majority Whip Sen. John Thune (R-SD), said that while they agreed with the president's take on repealing "Section 230" of the Communications Decency Act, it had nothing to do with defense spending and should be litigated in another way.