After declaring that “Congress has no higher responsibility than to ensure that the president has available all the tools necessary to protect the national security,” Ryan’s plan cuts virtually every security tool in the president’s arsenal that isn’t a gun. His plan slashes $7 billion from diplomacy, international development and democracy promotion over the next two years. After four years, the Ryan Republican Budget cuts those accounts by more than 20 percent.

Ryan and the putative GOP nominee have forgotten what our grandparents knew. After World War II, they followed up the greatest military victory in our nation’s history with the largest development program in human history. The Marshall Plan rebuilt Europe, bringing roads, schools, jobs and hope to a shattered continent. This wasn’t charity – it was strategy. Through diplomacy, development and support for democracy, our grandparents forged the alliance of democracies that held communism at bay for a half century, prevented another global conflict and won the Cold War.

That same alliance of democracies stands with us today in our efforts to prevent a nuclear Iran, and continues to fight alongside us in Afghanistan. Diplomacy and development in the 1940s laid the groundwork for American strength and leadership in the iPad age. Slashing the security tools that made us strong in the first place is no way to ensure future American leadership.

Ryan’s proposal increases the defense budget, but his single-minded emphasis on military spending ignores the reality of modern war. Our troops in Afghanistan know that fighting an insurgency requires diplomatic savvy and development expertise in addition to combat skill.

As an Army officer serving in Iraq and Afghanistan, my fellow soldiers and I relied heavily on diplomats and development professionals to get the job done. In Afghanistan, I served in and around the now-infamous Korengal Valley, leading a platoon of paratroopers in the enemy-saturated mountains along the Pakistani border. On a typical mission, my Humvee carried four men: myself and another paratrooper, a Pashto-speaking diplomat from the State Department and a development expert from the U.S. Agency from International Development.

Without that State Department diplomat, my fellow soldiers and I would have been flying blind in our frequent dealings with tribal elders and warlords. Without that USAID development expert, we would have had little to offer local leaders in exchange for their support against the Taliban. Even in the middle of a modern shooting war, it takes a whole of government approach to win.

America confronts a hyper-connected world. The security threats we face, from pandemic disease spread across oceans at the speed of a jet aircraft to the economic contagion that challenges our workers and the virulent terrorist networks that threaten our security, are born of this hyper-connectivity. We learned on September 11th that a plot created in the poverty-stricken villages of Afghanistan could change the Manhattan skyline.

To meet these challenges, we need every tool at our disposal -- and we need them sharp. You can’t fight bioterrorism or stop pandemic disease with a tank. You can’t ward off a cyber-attack with an aircraft carrier. And you can’t circle the wagons against a threat if you’ve only got one wagon.

If the 21st Century is to be another American Century, we must apply the lessons our grandparents taught us as we face a new and challenging future. Unfortunately, Chairman Ryan has forgotten those lessons. Let’s hope his colleagues are better students of history.

Breen is the vice president of the Truman National Security Project. As a Captain in the U.S. Army, he served in both Iraq and Afghanistan.