Main opposition leader Lee Jae-myung speaks during an intra-party leadership meeting held Wednesday (Yonhap)

The main opposition’s goal to bring President Yoon Suk Yeol to “judgment” through the upcoming April 10 legislative election, now faces major hurdles due to Yoon’s and the ruling party’s growing popularity, observers said Friday.

Democratic Party of Korea Chair Lee Jae-myung in recent weeks has repeatedly stressed the party’s goal to bring the Yoon Suk Yeol administration to “judgment” by winning the election.

In his visit to the political symbolic constituency of Jongno-gu on Monday, he asked voters whether they were “ready to bring the Yoon Suk Yeol administration to judgment,” in a speech.

However, critics say that the effects of the election pledge on voters have been slowly wearing off, with the growing approval rate for Yoon and the ruling party.

“Lee has been more vocal about bringing Yoon to judgment recently, apparently noticing People Power Party Chair Han Dong-hoon’s successful plan in (improving the popularity of the ruling party),” Lee Jun-han, a professor of political science at Incheon University said.

“This has made it unclear for Lee on how much the ‘judgment’ rhetoric will be successful,” he added.

According to a Gallup Korea poll released Friday, the approval rate for Yoon came to 39 percent this week. The survey involved 1,000 Koreans aged 18 or older.

The figure rebounded from 29 percent in the corresponding survey conducted early last month.

The support for People Power Party came to 37 percent, eclipsing the Democratic Party’s 31 percent.

The Democratic Party has also been grappling with an intra-party rift over the leadership’s decision to snub the non-mainstream faction in the party during the election candidate nomination process. In recent weeks, several lawmakers who were not Lee’s aides have openly criticized the leadership’s decision and left the party in protest.

Gyeonggi Province Gov. Kim Dong-yeon, who is closely affiliated with the Democratic Party, expressed concerns that the rift over the candidate selection process could disillusion some voters.

“I am worried that the (negative buzz surrounding) the candidate selection process is replacing the party’s goal to judge the current administration,” Kim said in a Friday radio interview.

“Supporters could get angry and leave over the conflicts stemming from the candidate selection and the tension among different factions within the party.”

The Democratic Party's goal, however, could still materialize, with Yoon's disapproval rate standing at 54 percent in the latest Gallup Korea survey.

The voters' unresolved frustration over the stock manipulation scandal surrounding first lady Kim Keon Hee, coupled with Yoon's decision to veto a special bill calling for an independent investigation into the deadly Itaewon crowd crush in 2022, could work against the current administration, a political critic said. The bill was scrapped in a recent revote held at the National Assembly.

"Voters' frustration could increase slowly on Yoon's moves to veto certain bills," Lee Jong-hoon, a political commentator, said.