A TV screen shows an image of President Joe Biden and South Korean President Yoon Suk Yeol in Washington, at the Seoul Railway Station in Seoul, South Korea, on Thursday. Biden and Yoon unveiled a new plan Wednesday to counter North Korea's nuclear threat. The words read

A TV screen shows an image of President Joe Biden and South Korean President Yoon Suk Yeol in Washington, at the Seoul Railway Station in Seoul, South Korea, on Thursday. Biden and Yoon unveiled a new plan Wednesday to counter North Korea's nuclear threat. The words read "The South Korea-U.S. summit and adoption of the Washington Declaration." / AP

SEOUL, South Korea – The U.S. and South Korean governments have both hailed the "Washington Declaration" by the two nations' presidents as measures that will strengthen an alliance that turns 70 this year.

But Wednesday's declaration has been met with mixed reviews in Seoul. Some, especially from the ruling party, are favorable, and suggest that the deal will ease anxieties about the threat the South faces from North Korea's ever-larger nuclear arsenal. But there has also been an outpouring of criticism that the deal resulted in Seoul giving more than it got — and that it could make South Korea's neighborhood a more dangerous place.

President Biden promised this week that any North Korean nuclear attack against the U.S. or its allies "will result in the end of whatever regime" launched it. Biden's remarks were apparently intended to deter North Korea, but some in Seoul did not find the promise of U.S. nuclear retaliation very comforting.

"Isn't everything over for the Korean Peninsula the moment North Korea launches a nuclear attack?" opposition Democratic Party lawmaker Youn Kun-young asked in an interview with Korean broadcaster CBS radio. "No one on this small peninsula will be spared," he said. "What good will it do to strike back?"

One feature of the declaration is the promise to establish a consultative body intended to give Seoul more of a say in how the allies deter North Korea.

The people of South Korea will "feel that they are sharing nuclear weapons with the United States," enthused South Korean deputy national security adviser Kim Tae-hyo.

But Edgard Kagan, the U.S. National Security Council senior director for East Asia and Oceania, denied that this was a form of de facto "nuclear sharing" of the sort the U.S. and NATO members have.

Sending submarines could be a risky gesture of reassurance

One key military aspect of the declaration is the U.S. promise to dispatch a nuclear ballistic missile submarine to South Korea for a visit at an undisclosed date, to deter North Korea and demonstrate Washington's resolve to defend its ally. But experts see this as a symbolic gesture that comes with risks.

"We could strike North Korea with the sub thousands of miles away, so showing up in port in South Korea is about making our presence known," says David Silbey, an expert on military history and defense policy at Cornell University.

The problem with that, he says, is that "missile submarines aim to hide in deep water; putting them in the relatively shallow Sea of Japan" — or East Sea, as South Korea calls it — "makes them much easier to see and that will make the U.S. nervous."

It's also likely to make Beijing nervous, but a senior Biden administration official told reporters this week, "We are briefing the Chinese in advance and laying out very clearly our rationale for why we are taking these steps."

Is the deal tougher on Seoul than Pyongyang?

Much of the criticism centers on the fact that the declaration emphasizes South Korea's commitment to abide by the Nuclear Nonproliferation Treaty.

Yoon suggested in January that South Korea might have to acquire its own nuclear weapons. Some observers in the U.S. and South Korea see that as Seoul's sovereign choice. But the declaration's language appears aimed at quashing any such aspirations.

One thing that looks particularly bad for Yoon is that some of the harshest criticism is coming from conservatives who would normally be expected to leap to his defense. An editorial in the conservative Chosun Ilbo, for example, called the Washington Declaration a set of "shackles" on the South.

"Wednesday's declaration seems to put more emphasis on American concerns that South Korea could develop its own nuclear weapons than on the North Korean nuclear threat that prompts such aspirations," it said. "Ultimately, South Korea must be in a position to defend itself."

Win-win deals or protectionism?

Yoon and Biden also touted progress in the U.S.-South Korea economic alliance. In particular, Biden said that South Korean companies have invested more than $100 billion in new projects during his administration, creating over 40,000 new jobs including in hi-tech industries, such as semiconductors and electric vehicle batteries.

But many South Korean business leaders chafe at what they see as protectionist policies — from requests to reveal sensitive business information to pressure to build factories in the U.S. and limit business with China.

Hong Hyun-ik, a senior research fellow at the Sejong Institute, a think tank outside Seoul, suggested in an interview with Korean public broadcaster KBS that self-interested U.S. behavior on economic issues has worrying implications for the alliance as a whole, including U.S. security guarantees.

"If you look at the issue of semiconductors, batteries or EVs," he commented, "would the U.S. really sacrifice its own interests to protect South Korea?"

NPR's Se Eun Gong contributed to this report in Seoul.

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