Look for Vice President Harris to pursue the Biden Administration’s tough posture of defensive alliances in Asia if she runs for president in November. Although inexperienced in foreign affairs, the Coast Democrat has signaled that she would follow President Biden’s lead in building on America’s alliances with Japan and South Korea — and on the defensive network known as Aukus, the acronym for Australia, the United Kingdom, and the United States of America.

The vice president, visiting the Demilitarized Zone between North and South Korea in September 2022, declared, “I cannot state enough that the commitment of the United States to the defense of the Republic of Korea is ironclad and that we will do everything in our power to ensure that it has meaning in every way that the words suggest.”

Those words appear more relevant today than ever — and not just because Ms. Harris is now the likely Democratic candidate for president. On Monday, nearly 71 years since the signing of the truce that, on July 26, 1953, halted the fighting in the Korean War, the North’s party newspaper accused Seoul and Washington of having staged war drills against the North “without pause since the signing of the armistice.”

Ms. Harris’ words contrast with those of President Trump, who even now holds out the possibility of fresh talks with the North’s  Kim Jong-un, whom he first met at their Singapore summit in June 2018. In their second summit, at Hanoi in February 2019, they got nowhere, as they did four months later in an impromptu meeting at the DMZ when Trump was visiting South Korea.

Trump, however, holds out the vision of renewing the dialogue. “We stopped the missile launches from North Korea,” he said in his inauguration speech at Milwaukee. “Now, North Korea is acting up again,” he acknowledged. “I get along with him. He’d like to see me back, too. I think he misses me, if you want to know the truth.”

The prospect of Trump returning to the White House arouses concerns among American allies in view of his avowed determination to call for South Korea to increase the $1 billion it’s contributing this year for American bases. He and his vice presidential candidate, Senator Vance, have indicated they would reduce the number of American troops in Japan from the current level of about 53,000, more than in any other country, and in South Korea, now about 28,500.

Ms. Harris, as vice president, has upheld America’s commitments, showing no sign of diverging from the relatively tough policy pursued by Mr. Biden. On a visit to Yokosuka Navy Base in Japan nearly two years ago, she accused the People’s Republic of China of “undermining key elements of the international rules-based order.” Communist China, she said, “has challenged freedom of the sea” and “has flexed its military and economic might to coerce and intimidate its neighbors.”

As for the Republic of China on Taiwan, she’s stated her commitment to the defense of the independent island democracy, vowing to uphold “peace and stability in the Taiwan Strait” over which Red China regularly sends warplanes on intimidation flights ordered to preempt any impulses Taiwan’s leaders might have to declare independence from the Chinese mainland. The Taiwan Strait, she said, is “an essential feature of a free and open Indo-Pacific.”

In the Philippines, American forces are opening several small bases after having withdrawn from its major naval and air bases in 1992. The Philippines has clashed repeatedly with the Chinese over rights to the South China Sea, all of which China claims as its own.

For the moment, Communist Chinese and Philippine negotiators have concluded a deal for resupplying an old Philippine vessel that’s been moored for years on a disputed shoal. The Communist Chinese Coast Guard still controls the sea, and the next American president could be forced to decide how strongly to press the view that those are international waters, open to all sides.