President Donald Trump's budget would increase military spending by about $54 billion dollars, while cutting the State Department's budget by $11 billion, or 28.7%, in large part by slashing aid and development funds.
Reducing the investment in diplomacy, aid and development will make the US ultimately less safe, argued retired four-star Gen. George Casey, the former commanding general in Iraq from 2004 to 2007.
"It's important not to see this as just a nice thing to do," Casey told CNN during his visit to Capitol Hill. "It's an important tool of national security policy."
"I happen to be one of those people who believe we're in a long-term ideological struggle against Islamic extremism and instability is our enemy because it feeds those groups," said Casey, who also served as Army chief of staff from 2007 to 2011, overseeing operations in Afghanistan.
"Raising prosperity, increasing a country's ability to protect itself, contributes to stability, reduces instability," Casey said.
Casey was joined by about a dozen other retired three- and four-star generals who fanned out across Capitol Hill to visit lawmakers from both Houses and parties to press the case for better funding for diplomacy. Casey's list of lawmakers included Sen. Tom Cotton, an Arkansas Republican who served in Iraq and Afghanistan and sits on the Armed Services Committee, as well as Sen. Chris Murphy, a Connecticut Democrat who sits on the Senate Foreign Relations Committee.
The generals are also focusing on lawmakers who are on appropriations committees that control funding, according to the US Global Leadership Coalition, the non-profit group organizing the visit.
Last month, the group rallied more than 120 retired generals and admirals to write the White House in protest of the proposed cuts to diplomacy and development. Retired Gen. David Petraeus, a former CIA director, and retired Adm. James Stavridis, the former NATO supreme allied commander, were among those who wrote that State Department funding is "critical to keeping America safe."
Development and diplomacy reduces the work the military has to do, Casey and others, including Secretary of Defense James Mattis, have said.
Casey added that in today's world, there are jobs the military just can't do. "The hardest thing for the military is to be thrust into a problem that can't be solved by military means," Casey said.
"If we've learned anything since (the terror attacks of) Sept. 11 from the military side, it's that the challenges we face today don't necessarily lend themselves to pure military solutions," Casey said. "It takes military, diplomacy and development -- that's the lesson, that we need all those tools to succeed today."