The governor of the South Korean Island province of Jeju could hardly understand why the South Korean president, Yoon Suk-yeol, wasn’t on hand for a memorial service in Jeju’s vast Peace Park. The service, after all, was to mark the 76^th anniversary of the outbreak of a crackdown on Communists and leftist sympathizers. 

“We want him here, but he sends his prime minister instead,” Governor Oh Young-hun tells the Sun “We would like to know that he cares about us.” 

Memories of the slaughter of between 25,000 and 30,000 people, by official estimate, between April 3, 1948, and the end of the Korean war five years later, burn deeply into the subconscious of the 700,000 people living on Jeju, 60 miles south of the Korean peninsula at the nearest point. Stories of the massacre endure among the dwindling numbers of survivors, who pass them on to their children and grandchildren, warning them never to forget the cruelty of government forces. 

It comes as no surprise that the majority of voters on Jeju favor candidates of the left-leaning Minju or Democratic Party in crucial elections Wednesday for the country’s National Assembly that may determine the future of the government of the conservative president, Yoon Suk-yeol. 

Although sentiment on Jeju, a scenic island that attracted more than 14 million visitors last year, may be extreme, it epitomizes the feelings of what may be a majority of the voters who blame Mr. Yoon for inflation, sky-rocketing home prices and job losses in a flagging economy. 

“Nobody’s happy,” said an office worker, Kim Sang-eun. “Prices are going up. Owners of small stores are not doing well. People are losing jobs.” 

Discontent on Jeju and the closest southwestern Korean provinces may be more serious than elsewhere, but there is no doubt that economic malaise, more than any other factor, dominates campaigning for all 300 assembly seats. In a complicated system, voters will cast ballots for 254 assembly members and also vote for separate  political parties, which select the remaining 46 members on a proportional basis.

Much will depend on the performance of Mr. Yoon, who defeated the leftist candidate, Lee Jae-Myung, by about one percent in the presidential election two years ago. The opposition Minjoo party holds in the assembly a slim majority over Mr. Yoon’s People Power Party. An increase in seats would make it difficult for him to ram through his legislative program in the remaining three years of the single five-year term to which Korean presidents are limited.

“Around 55 percent or 60 percent think the president is not doing a good job,” says the research director of Gallup Korea, Heo Jin-jae, talking to correspondents at Seoul. “Around 35 percent think he’s doing a good job.” The election, he said, “is judgment day for the government.” 

Mr. Heo hedged, though, on how badly Mr. Yoon’s People Power Party is likely to do. “It is still very challenging to predict the number of seats,” he said, even though “overall progressives have about a 10 percent higher percent than conservatives.” 

The outcome will depend, he said, on “the moderate swing vote” as well as the degree of support for small groupings including the Rebuild Korea Party, whose leader, Cho Kuk, still faces charges stemming from a corruption scandal. 

Incredible though it may seem to foreign observers, voters do not appear much divided over Mr. Yoon’s decision at the outset of his presidency to adopt a tougher policy toward North Korea than his liberal predecessor, Moon Jae-in, who failed at reconciliation with North Korea’s leader Kim Jong-un. Mr. Yoon has reinstated joint military exercises with American troops and met Japan’s prime minister, Fumio Kishida, in talks hosted by President Biden at Camp David last August. 

Surveys showed that most voters believe Mr. Yoon “is doing a good job in terms of foreign relations but a bad job related to the economy,” Mr. Heo told correspondents.

On the island of Jeju, Governor Oh believes Mr. Yoon missed an opportunity to win votes by not coming down for the ceremony memorializing victims of massacres conducted largely at the behest of South Korea’s first president, Syngman Rhee. “President Yoon doesn’t like to remember or pay tribute to the victims,” Mr. Oh tells the Sun. “I want Mr. Yoon to say, ‘I’m sorry.’”