President Trump's budget faces blowback for slashing State Department funds Former top military leaders and congressional leaders are speaking out.

 -- The full details of President Trump’s budget aren’t even out yet, and already the blowback against the White House is, in a word, tremendous.

Former top military leaders who served on the frontlines and congressional leaders in the president’s party are all speaking out, trying to stop the administration from slashing funds for foreign aid and American diplomacy.

"It's going nowhere," Sen. Lindsey Graham, R-S.C., said of the likelihood that Congress would approve such a budget.

"Probably not," said Senate Majority Leader Mitch McConnell, R-Ky.

The White House announced Monday that it wants a 10 percent increase in military spending, roughly equal to $54 billion, with an equal amount of cuts from the “non-defense” budget -- historic levels not seen since the early Reagan administration.

Executive agencies, including the State Department, are reviewing the plan now before the White House submits a final budget to Congress by March 16, but there have been reports that the plan could include up to a 30 percent cut to the State Department’s budget or the elimination of whole divisions, such as the envoys for climate change and anti-Semitism.

While the administration gave no details, Mick Mulvaney, director of the Office of Management and Budget, said foreign aid would be a top priority to cut.

“The president said we're going to spend less money overseas and spend more of it here. That's going to be reflected with the number we send to the State Department,” Mulvaney said Monday.

The State Department wouldn’t confirm any numbers, but acting spokesman Mark Toner said in a statement, “The Department is working with the White House and OMB to review its budget priorities ... [and] remains committed to a U.S. foreign policy that advances the security and prosperity of the American people."

Secretary of State Rex Tillerson met with Trump at the White House on Monday, but it remains unclear how hard the former businessman will push back on proposed cuts. The budget for the State Department and foreign aid together totaled $50.1 billion last year.

But the White House proposal drew a sharp response from even Republicans on the Hill.

Sen. Graham blasted the idea, telling reporters it would not stand a chance in Congress.

“This budget destroys soft power, it puts our diplomats at risk, and it's going nowhere,” he said today. “Clearly they don't understand how soft power is essential to winning the war.”

Sen. Marco Rubio, R-Fla., a foreign policy hawk like Graham, tweeted his opposition as well.

“Foreign Aid is not charity. We must make sure it is well spent, but it is less than 1% of budget & critical to our national security,” the former Republican presidential candidate wrote.

Even the normally reserved Republican leader Mitch McConnell shot down the idea.

"I for one, just speaking for myself, think the diplomatic portion of the federal budget is very important, and you get results a lot cheaper frequently than you do on the defense side," he said. "So, speaking for myself, I’m not in favor of reducing what we call the 150 account to that extent," using a Washington term for the international affairs budget.

Over 120 retired senior military leaders also wrote a letter to Congress, urging it to save the State Department’s budget out of “our strong conviction that elevating and strengthening diplomacy and development alongside defense are critical to keeping America safe.”

“Many of the crises our nation faces do not have military solutions alone,” they wrote, highlighting the foreign service’s non-military counter-terror tools and calling for “strong civilian partners in the battle against the drivers of extremism -- lack of opportunity, insecurity, injustice, and hopelessness.”

They also cited foreign aid’s role in addressing other challenges, from efforts to prevent and contain epidemics like Ebola, to support for fragile but vital ally governments or the world’s 21 million refugees.

“Now is not the time to retreat,” wrote the military leaders, including David Petraeus, the former top commander in Iraq and Afghanistan and CIA director. Most recently, he was considered for national security adviser, meeting with President Trump but ultimately withdrawing his name.

The list also includes prominent leaders like former National Security Agency and Cyber Command chief Keith Alexander, former top Iraq war commander George Casey, former top Afghan war commander John Allen, and former Marine Corps commandants James Conway, Michael Hagee and Charles Krulak.

Almost all of the signatories to the letter are not politically involved, but two were big Trump critics: John Allen, was a vocal Hillary Clinton campaign supporter, and Michael Hayden, who was George W. Bush’s CIA director and was a Never Trumper.

ABC News’ Ali Rogin and Luis Martinez contributed to this report.