When President Obama lifted the ban on U.S. weapons sales to Vietnam, he invoked one of his favorite themes — relics of the Cold War.

"This change will ensure that Vietnam has access to the equipment it needs to defend itself and removes a lingering vestige of the Cold War," Obama said Monday in the capital, Hanoi.

He sounded a lot like the president who made a groundbreaking visit to Cuba in March:

"I have come here to bury the last remnant of the Cold War in the Americas," Obama said in Havana.

And in making his case for the Iran nuclear deal last August, he spoke at American University in Washington, the same place President Kennedy chose to herald the landmark Nuclear Test Ban Treaty in 1963, at the peak of the Cold War.

"He rejected the prevailing attitude among some foreign policy circles that equated security with a perpetual war footing," Obama said of Kennedy.

When the Soviet Union collapsed on Christmas Day in 1991, Obama had just graduated from law school. Yet when he entered the Oval Office, the U.S. was still keeping its distance from some old rivals still run by authoritarian leaders.

Some foreign policy analysts argued this was as it should be, saying the world's lone superpower had no compelling reason to make concessions to smaller, weaker, undemocratic regimes that violate the liberties of their citizens.

Conservative Republicans and human rights groups have both criticized him, and some took issue with his latest move in Vietnam, which is still under communist rule.

"In one fell swoop, President Obama has jettisoned what remained of U.S. leverage to improve human rights in Vietnam — and basically gotten nothing for it," said Phil Robertson, who follows Asia for Human Rights Watch.

"We simply can't give a pass to the Vietnamese regime and a pass to their oppressive government," said John Cornyn, a Republican senator from Texas, who has introduced legislation that would impose sanctions on Vietnamese nationals linked to human rights abuses.

The president has argued that the U.S. opted for sanctions, boycotts and other punitive measures for decades, yet failed to bring about the changes sought. He's replaced Cold War standoffs with diplomacy and engagement that he says are in the service of larger goals.

Improved ties with Vietnam and Myanmar reflect his "pivot to Asia," the notion that the U.S. should place greater political, economic and strategic emphasis on the region. The Iran deal is part of his attempt to prevent nuclear proliferation worldwide and de-escalate tensions in the Middle East.

It's impossible to measure how much influence Obama's policies have or haven't had on the governments involved. But the president has certainly carved a new path.

He's the first sitting president to visit Cuba in nearly 90 years. The Obama administration has had more contact with Iran than any other since that country's 1979 Islamic Revolution. And he was the first president ever to visit Myanmar, a country where generals ruled directly or indirectly for more than a half-century.

But since March, Myanmar's government has been guided by Aung San Suu Kyi, the Nobel Peace laureate. She's not allowed to formally hold the title of president, and the generals still have considerable clout, but the change has been substantial.

Meanwhile, Iran has abided by the terms of the nuclear deal so far, according to those monitoring the agreement, though it has continued with provocative steps like missile testing that are not covered by the deal.

In Vietnam, where the U.S. restored diplomatic relations two decades ago, ties between the two countries have steadily improved. Still, Obama did reverse U.S. policy on Monday by agreeing to sell weapons.

Obama met with dissidents and nudged Vietnam's leaders to improve human rights in remarks in Hanoi on Tuesday. But he focused on the rapidly expanding economic ties.

"You'll be able to buy more of our goods, made in America," Obama told the audience. "There are strategic benefits: Vietnam will be less dependent on any one partner, and enjoy broader ties with more partners, including the United States."

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