It is regrettable that the US is pressing Seoul harder than ever, despite a backlash from South Koreans, to increase to exorbitant levels its share of the cost of keeping American troops on its soil.

In a rare sight, the US negotiating team walked out of the third round of defense cost-sharing talks on Tuesday. James DeHart, the US chief negotiator, said the US side had “cut short” the meeting to give Seoul more time to “put forward new proposals.” He said the Korean proposals were “not responsive to our request for fair and equitable burden-sharing.”

The US side reportedly holds the position that a new article should be added to the cost-sharing deal, drastically increasing Korea’s share of the defense costs. The Korean side maintains that the increase should stay within mutually acceptable bounds and within the framework of the accord that both sides have agreed to over the past 28 years.

Rep. Lee Hye-hoon, head of Korea’s parliamentary intelligence committee, said in a radio interview on the same day that US Ambassador to Korea Harry Harris had “repeated the demand to pay $5 billion for defense cost-sharing about 20 times” when she met him earlier this month. It is disappointing that even the US envoy, who is no doubt well aware of the importance of the US-Korea alliance, repeated the demand so many times on one occasion.

US Defense Secretary Mark Esper refused to prognosticate or speculate when asked Tuesday whether the US would consider reducing the number of its troops in Korea, in the absence of a mutually acceptable deal. Considering that four days earlier, he had reaffirmed the US position that US forces in Korea would be maintained at their current scale, his ambiguous answer can be interpreted to mean that Washington may use the US troops in Korea as a bargaining chip in the defense cost-sharing talks. Esper also said Korea is “a wealthy country that can and should contribute more.”

Washington seems determined to turn the screws hard on Seoul. The two sides have had to overcome differences each time they negotiated a defense cost-sharing deal, but this time the US pressure seems much greater than normal. The US is shaking the alliance over money issues. This would have been unthinkable for past US and Korean administrations. Trump has criticized US allies, including Korea and Japan, for supposedly “free riding” on American security commitments. Probably, DeHart, Esper and Harris are acting on orders from Trump, who apparently values money over alliances.

Demands for a jaw-dropping fivefold increase in Seoul’s share of the upkeep cost for US forces -- from $924 million for this year to nearly $5 billion for next year -- go against common sense. Seoul made big concessions last year, hiking its contributions by 8.2 percent and shortening the renewal period for the defense cost-sharing accord from five years to one year.

Korea shouldered $9.8 billion, 91.6 percent of the total cost ($10.7 billion) of expanding Camp Humphreys in Pyeongtaek, Gyeonggi Province, about 70 kilometers from Seoul, into the largest US overseas military base in the world. Korea was the third-largest importer of US-made weapons from 2008-2017. As its ally, Korea has contributed sufficient support for American troops on its territory.

The US needs to be aware of the growing backlash against its excessive demands. Over the past week, civic groups have rebuked Washington for putting so much pressure on Seoul, calling its actions “extortion of taxpayers’ money.”

The backlash has spread from civic groups to lawmakers. Ruling Democratic Party lawmakers on the National Assembly’s Defense Committee have vowed not to ratify any deal that deviates from the established principles that governed previous agreements.

The floor leaders of the ruling party and the two largest opposition parties headed to Washington on Wednesday to help narrow the two allies’ differences over the defense cost-sharing agreement.

Lawmakers of the Assembly’s Foreign Affairs and Unification Committee plan to visit Washington early next month to meet US House representatives and senators to explain Korea’s position.

Although the withdrawal or reduction of US troops would present a critical issue for both sides, Washington mentions the possibility with nonchalance. The US troops are not here only for Korea, but also serve as an outpost against China. Washington must refrain from pressing Seoul with excessive demands and must instead listen to Koreans, who want a reasonable and fair deal based on the spirit of mutual benefit and an airtight alliance.