Amid the escalating South Korea-Japan conflict, the US is expected to turn up pressure on South Korea over diplomacy and security issues.

Major issues between Seoul and Washington include South Korea’s share of US Forces Korea upkeep costs, the protection of shipping lanes off the coast of Iran and the deployment of US intermediate-range missiles.

US Secretary of Defense Mark T. Esper came to Seoul late Thursday afternoon. He will hold talks with his South Korean counterpart, Jeong Kyeong-doo, on Friday.

“Talks have begun to further increase payments to the United States,” US President Donald Trump said on Twitter on Wednesday. “South Korea is a very wealthy nation that now feels an obligation to contribute to the military defense provided by the United States of America.”

His words are noteworthy in that they came a day before Esper’s visit to Seoul.

US Secretary of State Mike Pompeo said South Korea, along with other countries, has a stake in protecting vessels in the Strait of Hormuz. Seoul is reportedly considering sending an anti-piracy unit off Somalia to the strait, though the government has maintained that it continues to look into various options.

Missile deployment is a controversial issue.

“I have never asked anybody about the deployment of missiles in Asia,” Bloomberg quoted Esper as saying Wednesday. “We are quite some ways away from that. It’s going to take, again, a few years to actually have some type of initial operational-capable missiles, whether they are ballistic, cruise -- you name it, to be able to deploy.” Though this issue is unlikely to be on the table during the defense ministers’ talks, it will probably be raised someday.

On Saturday, a day after the US formally pulled out of the Intermediate-Range Nuclear Forces agreement with Russia, known as the INF treaty, Esper said he was in favor of deploying ground-based missiles to Asia, according to the New York Times.

US national security adviser John Bolton said Tuesday that the US’s willingness to deploy midrange missiles in Asia has to do with protecting its allies -- South Korea and Japan.

China’s Foreign Ministry said it will not just sit idly by, and threatened to take countermeasures if US midrange missiles are deployed to Asia.

Asked by lawmakers Tuesday about the possibility of US intermediate-range missiles being deployed in South Korea, President Moon Jae-in’s chief of staff Noh Young-min said Korea has “never discussed it (with the US), nor reviewed it nor plans to do so.” He added, “Our position will never change,” even if the US demands it strongly.

It is understandable that South Korea wants to avoid China’s retaliation for deploying US missiles. But a flat refusal even before any discussion gives the impression that Seoul stands by Beijing.

China, not part of the INF, reportedly already has thousands of intermediate-range missiles deployed. That is one reason Trump withdrew from the treaty.

North Korea launched missiles similar to the hard-to-intercept Russian-made Iskander. They can reach the site of the US Terminal High Altitude Area Defense antimissile systems in South Korea. The North has also perfected nuclear weapons. Seoul needs to draw Beijing’s attention to this situation and keep all possibilities open when it comes to security.

Who knows what will happen?

Five aircraft from China and Russia recently violated South Korea’s Air Defense Identification Zone, with one invading its airspace. While China, Russia and North Korea formed a united front, security cooperation between the US, Japan and South Korea appears unstable.

The South must keep in mind that the US alliance is the only recourse for its security. If the alliance breaks up, South Korea will be left alone. The North will provoke more boldly. Seoul must not undermine it in furthering its national interests.

Chung Eui-yong, director of the National Security Office, told lawmakers Tuesday that North Korea’s recent missile launches were not a big threat to South Koreans. He also said they did not violate the inter-Korean military agreements that preclude either side from taking hostile acts against the other.

Considering Cheong Wa Dae’s divergent responses to North Korea and China on the one hand, and Japan on the other, it is questionable whether the current government has the ability to act wisely. That worries people.