President Obama, fresh from an Asia-Pacific Economic Cooperation meeting in Honolulu, flew to Canberra and Darwin in Australia and to Bali in Indonesia last week to confront China with an olive branch in one hand and a sword in the other.

In an address to Parliament in Canberra, the president sought to assure China — and other Asian nations — that America’s intent was peaceable. “The United States will continue our effort to build a cooperative relationship with China,” he said, since all nations “have a profound interest in the rise of a peaceful and prosperous China.”

“We’ll seek more opportunities for cooperation with Beijing, including greater communication between our militaries to promote understanding and avoid miscalculation,” he continued. The president has sought for months to persuade China’s leaders that the U.S. is not trying to “contain” their nation’s spreading influence.

In Bali for a gathering of political leaders from 18 Asian and Pacific nations, President Obama reiterated that assurance but was also vigorous in advocating maritime security, a code word for keeping open the international sea lanes through the South China Sea.

His stance drew nods of assent from most of the leaders assembled for an East Asian Summit. Those sea lanes are vital to Asian economies because through them flows more shipping each year than through the Suez and Panama canals combined.

The U.S. has insisted on freedom of navigation through the South China Sea because U.S. warships frequently sail though those waters between the Indian and Pacific Oceans. Indeed, some American officers contend that whoever controls the South China Sea would control the rest of Asia.

In contrast, Chinese spokesmen said that China had been “consistent and clear” in its posture. They have repeatedly asserted that China has “indisputable sovereignty” over the South China Sea.

Moreover, they argue that disputes there should be resolved through negotiations between China and other nations separately — so that China could bring to bear its full power against its weaker neighbors one by one.

The U.S. has insisted, however, that negotiations should include every nation with interests in the South China Sea, including the U.S., Japan, Taiwan, and South Korea, and not just those whose shores are washed by those waters.

President Obama, who met with Premier Wen Jiabao at Mr. Wen’s request on the sidelines, presumably reiterated the U.S. position even though the Chinese press said their conversation focused on economic issues. Mr. Wen also met with Australian Prime Minister Julia Gillard and Singaporean Prime Minister Lee Hsien Loong.

Even as he proffered an olive branch to China, President Obama sought to add muscle to American security relations in the region. During a stop at a military base in Darwin in northern Australia, the president met with Australian soldiers and U.S. Marines.

“We’re celebrating the 60th anniversary of our great alliance,” he said. “And we couldn’t think of a better group to do it with than you. All of you are the backbone of our alliance. It’s an honor to be here with Australia’s legendary Diggers. You are some of the toughest warriors in the world. And so are another group of folks here today — our extraordinary United States Marines.”

Accompanied by Prime Minister Gillard, the president said: “Here in Darwin and Northern Australia, we’ll write the next proud chapter in our alliance. As the Prime Minister and I announced yesterday, some of our Marines will begin rotating through these parts to train and exercise with you, and to work as partners across the region for the security we all want.”

Later, in Bali, American officials disclosed that the U.S. would provide 24 refurbished F-16 jet fighter planes to the Indonesian air force to patrol the southern shores of the South China Sea. In addition, the U.S. would provide 12 Black Hawk helicopters to Brunei. Those versatile aircraft can be used against terrorists or pirates at sea.

Further, the president conferred individually with leaders from Singapore, Malaysia, and India. Before meeting with Prime Minister Manmohan Singh of India, considered a coming rival with China, the president said he was pleased that India and the U.S. could “work together on a wide range of issues, such as maritime security or nonproliferation.”

The president announced that he had asked Secretary of State Hillary Clinton to visit Burma, or Myanmar, next month to explore reconciliation between the U.S. and the autocratic government there. Although U.S. officials were cautious in briefing the press, it was clear the U.S. would seek to douse Chinese influence in a nation on its borders.

Perhaps most important, President Obama assured Asian leaders that he would see to it that the forthcoming budget cuts in Washington would not affect the U.S. security posture in Asia even as the defense budget took its share of hits.