BEIJING, April 28 -- U.S. President Barack Obama starts on Monday a high-profile visit to the Philippines, the last stop of his four-country Asia swing designed to bolster rebalancing to the region.

Hours before Obama's arrival, Washington and Manila signed a defense accord to enhance their military cooperation, which would allow a greater U.S. military presence in the Southeast Asian nation.

Given that the Philippines is at a bitter territorial row with China, the move is particularly disturbing as it may embolden Manila in dealing with Beijing. A more assertive or even reckless Manila would stoke regional tensions and in turn upset Obama's policy of rebalancing.

It is noteworthy that the Philippines has been a trouble-maker in the South China Sea. It has encroached upon Chinese territory and harassed Chinese fishing boats.

Its repeated provocations triggered a fierce standoff two years ago in the waters off the Huangyan Island, an integral part of China whose surrounding waters have been traditional fishing grounds for Chinese fishermen.

After tensions flared up in 2012, the Philippine government led by President Benigno Aquino turned its back on China. Despite Beijing's continuous efforts to seek a negotiated solution on bilateral basis and equal footing, the Aquino administration betrayed its commitment to talks and went its own way by seeking international arbitration at the end of last month.

By striking the defense deal with the United States at this moment despite domestic opposition, the Aquino administration has made its intention clear: to confront China with U.S. backing.

Such an aggressive posture could easily lead to further provocation. An emboldened Aquino would make an amicable solution to the territorial disputes more difficult, if not impossible, and intensify regional tensions.

It can hardly be said that this kind of scenario is what the United States wants to see with its "pivot to Asia" strategy. Washington has explicitly said that peace and stability in Asia accords with its own interests.

Throughout his four-nation trip in Asia, Obama is trying to strike a delicate balance between its "pivot to Asia" strategy and its ever-expanding relations with Beijing.

While assuring its jittery Asian allies of U.S. commitments, Obama also shattered their illusion that Washington might support them at all costs in their territorial disputes with China. He reiterated that the U.S. government takes no sides in those disputes.

Though its neutrality pledge has yet to be tested, Washington is fully aware that there is no easy fix to Asia's current slew of problems, and that the best way to solve them is to leave them to those countries directly involved.

Interpreting Washington's Asia strategy as a move to contain China is wishful thinking.

Just as Ted Galen Carpenter, a senior fellow at the Cato Institute, warned, it would be Washington's biggest strategic mistake to antagonize two major powers simultaneously when the United States is in the worst confrontation with Russia since the Cold War over Ukraine.

The Pacific Ocean is big enough to accommodate both the United States and China. As the world's two largest economies, they can help build a better future in Asia through cooperation.

Bearing that in mind, Washington should be wary of an emboldened Manila.