Secretary of State Hillary Rodham Clinton on Wednesday became the first high-ranking U.S. official to visit Laos since the Vietnam War era, when the United States dropped some 260 million cluster bombs across the countryside in a nine-year campaign to crush North Vietnamese supply lines and bases.

Clinton met with Laotian Prime Minister Thongsing Thammavong and other officials for talks that centered mostly on addressing the lingering effects of that war — including a sense of mutual estrangement — and then toured a small museum devoted to its human toll.

In the sweltering afternoon, Clinton walked through an exhibit of dangling cluster bombs and crude wooden artificial legs made by villagers whose limbs had been blown off by unexploded ordnance, the legacy of a war that Clinton had protested as a college student in the 1960s.

Then she met Phongsavath Souliyalat, who had been blinded by and lost both hands to a cluster bomb. He told her he hoped governments would ban the weapon.

“We have to do more,” Clinton responded. “That’s one of the reasons I wanted to come here today, so that we can tell more people about the work that we should be doing together.”

The stop in Vientiane, Laos’s capital, was a brief but symbolically significant part of a longer trip that has also taken Clinton to Mongolia, Vietnam and, later Wednesday, to the Cambodian capital, Phnom Penh, where she was expected to attend Thursday’s regional meeting of the ASEAN group of 10 Southeast Asian nations.

The trip is intended to underline the Obama administration’s much-promoted strategic pivot toward Asia, and more particularly to convince ASEAN nations that U.S. interests in the region are not just security-based, but economic as well. Clinton is unveiling a range of economic initiatives and private-sector business deals during the trip.

At the same time, the United States is trying to encourage ASEAN nations to assert themselves in a simmering territorial dispute with China over the South China Sea, which analysts view as a test case for how a rising China will deal with the world — through threats and coercion or according to international legal norms.

China claims most of the South China Sea, including portions also claimed by the Philippines, Vietnam, Malaysia, Brunei and Taiwan, and the resolution of those disputes will determine not only fishing rights but the rights to potentially large reserves of oil and natural gas.

The United States has been pushing the ASEAN nations to unify around a legally binding code of conduct based on international maritime law as a means of managing the disputes and as a way of cultivating ASEAN as a partner in the larger mission of engaging China.

China essentially wants the United States to stay out of it, and it is unclear which way ASEAN nations will bend.Even if they do come up with a tough code of conduct, analysts say the Chinese are unlikely to sign on to it.

Finessing such complexities of the so-called Asia pivot has been Clinton’s job, and she has carried it out partly by showing up: She has attended every ASEAN regional conference, and with her trip to Laos on Wednesday, she has visited all of the 10 ASEAN nations except Brunei, many of them multiple times.

As her term as secretary of state winds down, analysts say, many Asian leaders wonder whether U.S. engagement will last.

“She’s carrying a lot of the water herself,” said Ernest Z. Bower, a senior adviser and director of the Southeast Asia program at the Center for Strategic and International Studies. “But when Asia looks at the U.S., they wonder if she has the support of the White House, of the political system, and that is a big question mark.”

After Clinton met here with Thongsing, her motorcade sped along bumpy, palm-tree lined roads, past people on sidewalks who stopped to stare. Later, she addressed U.S. and Laotian employees of the U.S. Embassy.

“Here in Laos,” she said, “the past is always with us.”