As war in Ukraine looms, land warfare is suddenly front and center again in discussions of U.S. national security.

But whatever happens in Ukraine, America’s strategic imperative is at sea. A look at the U.S. Navy — or at a map — makes clear the United States must keep its focus squarely on maritime competition and conflict.

President Joe Biden’s first defense budget, seeking $740 billion for the Department of Defense, was business as usual. The department initially requested $207 billion for the Navy (the Marine Corps included), $204 billion for the Air Force, and $174 billion for the Army — not quite the “rule of thirds,” but close enough. But it’s no longer time for business as usual.

The federal government has spent more than $3.54 trillion to address the ongoing COVID-19 pandemic and stabilize the economy, leading to record budget deficits. Despite this geyser of money, the U.S. defense budget is running into hard fiscal realities. A multitude of domestic issues, including declining birth rates, rising health care costs and soaring inflation, will pose significant challenges for U.S. policymakers in the years to come.

There is no easy way out. Some propose the Department of Defense “divest to invest”— phasing out older programs and weapon systems immediately to free up funds for modernization. Such a strategy, however, reduces current U.S. operational and deterrence capabilities. As Beijing is confronted with its own growing domestic problems — a rapidly aging population, slowing economic growth, and the consequences of the pandemic — it may determine its window of opportunity to achieve its geopolitical goals is closing. Divest to invest may invite unacceptable short-to-medium term risk.

Luckily, America is physically secure thanks to its geography, with friendly and weak neighbors to the north and south and immense oceans to the east and west. A large active-duty army is not needed to protect the United States.

America’s security interests are far better served through deterrence and the projection of power by sea and air. Given the geography of the Indo-Pacific and the reality of future spending constraints, ensuring U.S. naval supremacy over China will require prudent increases to the Navy’s budget at the expense of the Army.

Unfortunately, the United States Navy has, to put it starkly, squandered 40 years of peace. Faced with no major peer competitor for most of that period, a generation of civilian and uniformed Navy leadership indulged in transformational fantasies that yielded neither game-changing technologies nor affordable ships that could fight. The bill has now come due. The failures of the Littoral Combat Ship and DDG-1000 programs, and the serial overwork of an aircraft carrier fleet that may be en route to obsolescence, have yielded a shrinking and increasingly worn out fleet.

Though the U.S. Navy still possesses the world’s most capable fleet, China’s People’s Liberation Army Navy is closing the gap. China’s navy has already surpassed America’s in size.

But a strict comparison of navies is misleading. Any conceivable major war with China would be fought in the Western Pacific, where Chinese aircraft, drones, and the roughly 2,000 ballistic missiles of the People’s Liberation Army Rocket Force would be major factors. America’s Pacific allies would likely be a factor in any fight, but the volume and accuracy of Chinese missiles threatens to change the balance of power in Asia.

The United States Navy is also confronting a second foe every bit as dangerous as China: the defense budget. The Navy has now entered what one retired officer has termed “the Terrible Twenties:” a wholly foreseeable period of declining U.S. naval strength, due to a perfect storm of an aging population, legacy platform retirements and the recapitalization of the Navy’s strategic deterrent force.

There is another major factor to consider: a navy, moreso than any other instrument of military power, cannot be built overnight. It takes time to cut steel and lay keels, never mind build nuclear reactors and train the men to safely run them. Even in World War II, when American industrial capacity was unmatched, the majority of the fleet carriers that won the war in the Pacific had been ordered, and many laid down, before the attack on Pearl Harbor and U.S. entry into the war.

The time for temporizing is over. America’s national interests, geography, and fiscal situation point to the urgent necessity for a new maritime strategy. War in Ukraine, should it come, must not disrupt this critical shift. If the Biden administration is committed to checking China’s ambitions and preventing the rise of a hostile Pacific hegemon, it is running out of time to put the Navy first.

Gil Barndollar is a senior fellow at Defense Priorities, a think tank. Sascha Glaeser is a research associate at Defense Priorities.

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