When the Cold War ended with the collapse of the Soviet Union, the United States drew on its big lead in wealth, resources and technology to achieve an unprecedented level of global military dominance.

That “unipolar moment” appears to have been fleeting. Today the U.S. may be on the verge of a military decline that could have major repercussions for stability and the balance of power in the Asia-Pacific region.

Since 1999, America has put a high priority on being able to wage two major wars at the same time, in Asia and the Persian Gulf. In the very near future, it may no longer be able to do so.

America’s economy is laboring under accumulated debt. A partisan system of government in Washington seems far from agreement on a package of reduced spending and higher taxes. Agreement is needed — before a March 1 deadline set by Congress — to prevent further hefty and indiscriminate cuts in the armed forces’ budget over the next decade.

Top U.S. defense officials and service chiefs are deeply worried about the consequences of continued political deadlock. They have warned of a “readiness crisis” in the U.S. armed forces, as training and operations suffer from cumulative decline, undermining America’s ability to deter and respond to the threat or use of force in Asia and other parts of the world.

“We’ll have inadequate surge capacity at the appropriate readiness to be there when it matters, where it matters,” U.S. Chief of Naval Operations Admiral Jonathan Greenert told a congressional committee Feb. 13. “We will not be able to respond in the way the nation has expected and depended (on us to act).”

A day later, U.S. Deputy Defense Secretary Ashton Carter said that if lawmakers failed to forestall the so-called sequestration cuts, U.S. allies and rivals could conclude that the U.S. lacked resolve and was not serious in implementing the Obama administration’s new defense strategy. This includes a rebalancing of forces to the Asia-Pacific region, which Washington has identified as a key area for future economic growth, trade and investment. “Our friends and our enemies are watching us,” Carter said.

From 1999 to 2011, annual U.S. defense spending rose from $360 billion to $537 billion, not including an extra cumulative $1.3 trillion spent on operations in Afghanistan and Iraq. Total U.S. military spending in 2011 amounted to just over $739 billion, substantially exceeding the combined defense budgets of the next nine top spenders: China, Britain, France, Japan, Russia, Saudi Arabia, Germany, India and Brazil. So, there may be plenty of fat to cut. But it needs to be done in a carefully planned way.

President Barack Obama and Congress have already agreed to reduce the Pentagon’s budget by nearly $487 billion over the next decade. Sequestration is set to trigger another $500 billion in across-the-board cuts over the same period.

Carter says that compounding the impact of sequestration is the continuing resolution now funding the government, instead of a budget. Because an appropriations bill was not signed last year, some accounts for the military are underfunded while others have a surplus. “There’s enough money in the continuing resolution,” he explained. But “it’s in the wrong accounts.”

As a result, there is a cash shortage in the military operations and maintenance accounts.

The Pentagon has rushed through plans for operating the armed forces under sequestration. In the short term, this would mean subtracting $46 billion from the funds it planned to have available for the rest of this fiscal year, which ends in October.

Here is a summary of the U.S. military curtailments announced so far: The navy has indefinitely delayed the deployment of an aircraft carrier strike group to the Persian Gulf, the source of much of the imported oil and some of the imported natural gas that Asia relies on to power its economic growth.

Since 2010, two carriers and their surface warship and submarine escorts have been deployed to the Persian Gulf-Arabian Sea zone for most of the year, an operational tempo that has strained the fleet. The navy has also delayed the overhaul of a second carrier that is in service and delayed construction of one of the two being built.

The U.S. has 10 operational carriers, all nuclear-powered. They, and the 75 warplanes each carries, are the main weapon system America uses in projecting long-range power to deter aggression and fight in a conflict.

Admiral Greenert says an $8.6 billion shortfall in U.S. Navy operations and maintenance accounts “has compelled us to cancel ship and aircraft maintenance, reduce operations, curtail training of forces soon to deploy, and plan for the furlough of thousands” of civilian workers.

The air force plans to cut the flying hours of its pilots by 18 percent. It will also have to reduce air-to-air refueling, logistic support for the army and, by September, the training of new pilots. The army and marines will suffer similar hits to their training, maintenance and operations. More broadly, outgoing Defense Secretary Leon Panetta warned that sequestration would result in a substantially smaller army, navy and air force.

On Feb. 11, a group of 45 prominent U.S. security analysts and former officials wrote an open letter to congressional leaders warning that sequestration would be a dangerous and self-inflicted blow to American power and global leadership.

“It will degrade our ability to defend our allies, deter aggression, and promote and protect American economic interests,” they said. “It will erode the credibility of our treaty commitments abroad.”

Until now, the Obama administration has sought to maintain a global U.S. military presence that emphasized the Asia-Pacific region and the Middle East, while maintaining defense commitments to Europe. This global posture will be too expensive to maintain under sequestration — and possibly even under a better-planned alternative of U.S. defense reform over the next decade if sequestration is permanently averted.

Based on the actions taken so far by administration officials and U.S. service chiefs, the U.S. — if forced by austerity to change strategy — will focus its overseas presence more on Asia than the Middle East. This is because China’s military-backed push to carve out a sphere of offshore influence in the East and South China Seas, and ultimately control access to this zone, is judged to be an even greater threat to enduring U.S. interests than the situation in the Middle East.

This assessment could change if China showed greater restraint and Iran armed itself with nuclear weapons and the effective means to deliver them, threatening its neighbors and the flow of energy from the Persian Gulf.

Yet, Iran would still be rated a much lesser military challenge to the U.S. than China, and gulf energy resources of marginal interest to the U.S. compared with preserving unfettered access to its Asia-Pacific allies, regional economies and resources.

Michael Richardson is a visiting senior research fellow at the Institute of South East Asian Studies in Singapore.