WASHINGTON — In an unusual appearance at the White House briefing room, Defense Secretary James Mattis urged the House to go along with a two-year bipartisan spending deal struck by Senate leaders on Wednesday.

Addressing the White House press corps, Mattis made the case for the budget deal, which faces resistance from House Democrats and Republican deficit hawks just one day before government funding runs out and another shutdown looms. White House Press Secretary Sarah Huckabee Sanders said the agreement provides “much-needed increase in funding for our national defense, increases budget caps, ends the sequester, and provides certainty for the next two years.” The deal also extends the debt ceiling until March 2019.

Mattis told White House reporters that he was encouraged that “Congress recognizes the sobering effect of budgetary uncertainty on America’s military.” Repeating much of what he told the House Armed Services Committee at a Tuesday hearing, Mattis said the Pentagon needs “Congress to lift the defense spending caps and support a two-year budget agreement for our military. America can afford survival.”

He criticized the practice of using the military as leverage to pursue other political objectives. “We expect the men and women of our military to be faithful in their service, even when going in harm’s way,” said Mattis. “We have a duty to remain faithful to them.”

The deal would provide $700 billion for the military in fiscal year 2018 — with $71 billion in the overseas contingency operations account that is used to pay for war expenses. Funding would increase to $716 billion for fiscal year 2019, with $69 billion in the OCO account.

The request for fiscal year 2019 will go to Capitol Hill on Feb. 12. Mattis told lawmakers that the priority in the 2019 budget is to replace “yesterday’s weapons and equipment.” In the new request, he said, “You will see in our budget investments in space and cyber, nuclear deterrent forces, missile defense, advanced autonomous systems, artificial intelligence, and professional military education.” Mattis added that the increase would be “sufficient to begin down the trail to restore our competitive advantage that has been eroded.”

At the White House briefing, he said he remains “optimistic that what the House did earlier this week and what the Senate did today can come together this week and give us the budget that then enables us to carry out our responsibilities.”

Sandra Erwin writes about military space programs, policy, technology and the industry that supports this sector. She has covered the military, the Pentagon, Congress and the defense industry for nearly two decades as editor of NDIA’s National Defense...