On the sidelines of last month's G-20 summit, the United States acquiesced to Seoul's request for a three-year delay to the planned 2012 reversion of wartime operational control (OPCON) from the United Nations Command to the Republic of Korea.

The U.S. decision alleviates South Korean concerns that a premature OPCON transfer would dangerously undermine the country's defense.

It also signals strong U.S. support for its critical ally at a time of heightened tensions brought on by North Korea's heinous attack on a South Korean naval ship.

The Lee Myung-bak administration requested the delay, characterizing the demand for OPCON by his predecessor Roh Moo-hyun as a naive, ideologically-driven political decision that ignored military realities.

Moreover, the Cheonan sinking exposed dangerous deficiencies in South Korean military capabilities that might not be remedied by the planned 2012 transfer date.

While both assertions are correct, they oversimplify a complex issue by neglecting several critical factors.

The decision to delay does not address the underlying deficiencies of the plan. The deferment also alleviates pressure on Seoul to redress security shortfalls, including years of underfunded defense requirements.

Far more important than when OPCON transfer occurs is how it is done.

Unfortunately, the heated debate over timing has caused insufficient attention being paid to the more important manner of OPCON transfer.

The accompanying dissolution of Combined Forces Command (CFC) is dangerously ill-advised because it violates the key military precept of unity of command during hostilities.

The ability of a single commander to direct multi-service forces from two countries is irreplaceable in ensuring unity of mission and achievement of objectives.

Replacing a single integrated command with two parallel commands risks seriously degrading U.S. and ROK deterrent and war-fighting capabilities.

A bifurcated command also increases the danger of friendly fire casualties.

The current plan does not so much transfer OPCON as it divides it. Such a command structure is the equivalent of having two quarterbacks on the football field sending conflicting orders to the team.

Despite public assurances by the Pentagon and U.S. Forces Korea, serious concerns remain that the new command structure has greater potential for confusion or even tragedy during the fog of war.

The U.S. Congress and South Korean National Assembly should both hold public hearings to ensure that the alliance would retain sufficient ability to deter, defend and defeat any North Korean aggression.

Moreover, the delay in OPCON transfer shouldn't be used by Seoul as an excuse to continue underfunding its requirements.

Seoul has committed itself to Defense Reform Plan (DRP) 2020, an ambitious military modernization strategy to compensate for planned manpower reductions by upgrading to a smaller, high-technology defense force with improved command and control systems and more capable weapons.

However, years of defense funding shortfalls have undermined the program.

The plan prepared in 2005 identified the need for a cumulative 15-year budget of 621 trillion won (approximately $505 billion) and stipulated a 9.9 percent annual military budget increase for 2006 through 2010.

Instead, the average increase has been only 7.2 percent. There is now a projected 80 to 110 trillion won aggregate DRP 15-year budget shortfall.

The head of the Ministry of Defense Reform Bureau stated in 2008 that as a result of underfunding defense requirements, South Korea "can't even achieve the initial goals in the defense reform."

The Ministry of National Defense has requested a 6.9 percent increase in the 2011 budget, three points below the original plan.

Insufficient defense spending threatens the underlying premise of DRP 2020 which was that the increased quality of the residual military force would offset drastic cuts in the force structure.

Bruce Bennett, renowned military expert at the RAND Corporation, has speculated that South Korea could even find itself with a less capable military in 2020 than existed in 2000.

Just as the OPCON transfer should be seen in the broader context of DRP 2020 that in turn should be part of a strategic review of the proposed U.S.-ROK "strategic alliance."

Although the concept has been encapsulated in bilateral summit statements, actual progress on transforming the military relationship has been glacially slow.

Washington and Seoul should develop a joint strategic vision of the future purpose, objectives, and roles of the broader alliance and how it furthers the two countries national interests.

It will then be possible to identify the roles, missions, and required capabilities of the two militaries and then implement the broader alliance through procurement, deployment and training.

Although alliance managers have created a blueprint for Seoul assuming greater responsibility for the country's defense, identifying ROK regional and global security missions remain in the early stages, as reflected in protracted debate over Seoul's involvement in coalition operations in Afghanistan.

A major impediment has been the failure of the Lee administration to suitably articulate South Korea's envisioned role on the world stage.

President Lee advocates a "Global Korea" strategy commensurate with Seoul's political, economic, and military weight but has yet to define the country's international security responsibilities.

Seoul should develop a detailed strategic blueprint, similar to the U.S. National Security Strategy and National Military Strategy, that delineates South Korea's national interests, strategic policy objectives, and how the instruments of national power, including the military, would be employed to fulfill them.

Doing so would enable military planners to define security requirements and identify shortfalls even beyond those arising from the attack on the Cheonan.

As the recent 60th anniversary of the Korean War starkly reminded us, the U.S.-ROK alliance was forged in blood during the crucible of a brutal conflict.

The enduring bilateral relationship has been indispensable for defending South Korea and maintaining peace and stability in Northeast Asia.

Washington has demonstrated its support for a key ally by deferring the OPCON transfer. It is now Seoul's responsibility to use the delay wisely by articulating a plan to redress shortfalls in its defense capabilities and its commitment to the alliance by fully funding its security defense requirements.

The writer is a senior research fellow for Northeast Asia at the Heritage Foundation's Asian Studies Center.