The White House brought in Defense Secretary Jim Mattis Wednesday to press for a sweeping budget deal that would realize a long-sought Pentagon goal of lifting the caps on defense spending under the sequester process.

The proposal reportedly calls for about $700 billion in defense spending in fiscal 2018 and $716 billion in fiscal 2019 -- levels well above the sequestration caps mandated by the 2011 Budget Control Act.

Mattis pledged that "we will spend the money wisely" if a deal taking shape in the Senate is enacted that would guarantee defense spending above the sequester caps for two years and get around the stopgap funding of continuing resolutions that have mired the appropriations process for nearly a decade.

"I am optimistic" that the House and Senate will approve the deal, Mattis said in a rare appearance in the White House briefing room, though House Minority Leader Nancy Pelosi, D-California, warned that the proposal would face opposition unless immigration reform was included in the package.

The breakthrough proposal surfaced as the House and Senate faced another midnight Thursday deadline on a government shutdown, unless agreement was reached on either the budget deal or a continuing resolution that would put off agreement -- likely into next month.

White House Press Secretary Sarah Huckabee Sanders said earlier of the proposed deal, "The bottom line is that, thanks to President Trump, we can now have the strongest military we have ever had.

"This deal achieves our top priority -- a much-needed increase in funding for our national defense," she added. "This deal also increases budget caps, ends the sequester, and provides certainty for the next two years."

The proposed deal also included raising the debt ceiling and increases for domestic spending, which could make the package problematic for House Republicans.

"It also ensures funding for our other critical priorities, including rebuilding America's crumbling infrastructure, tackling the opioids epidemic, and taking care of our great veterans," Huckabee Sanders said.

Republican fiscal hawks were already lining up to announce their opposition to a deal agreed to by Senate Majority Leader Mitch McConnell, R-Kentucky, and Senate Minority Leader Chuck Schumer, D-New York, that they said would balloon the deficit.

"This budget deal is a betrayal of everything limited government conservatism stands for and I will be voting 'no,'" said Sen. Mike Lee, R-Utah.

McConnell said the agreement was "the product of extensive negotiations among Congressional leaders and the White House."

Anticipating opposition from deficit hawks, McConnell said in a Senate floor speech that "No one would suggest it's perfect, but we worked hard to find common ground and stay focused on serving the American people."

Huckabee Sanders said the proposal would give the military nearly $700 billion for Fiscal Year 2018. The $700 billion for defense was included in the National Defense Authorization Act passed last year by Congress and signed by Trump.

The money has been held up by a series of Continuing Resolutions that Congress passed because of its failure to reach agreement on the budget.

In addition to guaranteeing the $700 billion for fiscal 2018, the McConnell-Schumer proposal would give the military $85 billion more in fiscal 2019, which begins on Oct. 1. Non-defense spending would increase by $63 billion in this fiscal year and $68 billion next year, according to the New York Times.

Sen. John McCain, R-Arizona, chairman of the Senate Armed Services Committee, and Rep. Mac Thornberry, R-Texas, chairman of the House Armed Services Committee, had both argued for de-linking defense and non-defense spending, but they both endorsed the budget deal proposal coming out of the Senate.

In a joint statement, McCain and Thornberry said "This budget agreement finally does what we knew needed to be done from the beginning and funds our military at the level authorized in the National Defense Authorization Act" of nearly $700 billion.

"After nearly a decade of asking our troops to do more with less, we hope this agreement will allow the military to begin to rebuild and ensure that process can continue into next year," McCain and Thornberry said.

-- Richard Sisk can be reached at Richard.Sisk@Military.com.