(Bloomberg) -- South Korea’s Yoon Suk Yeol, a former prosecutor who made his name taking down a president, must now show he can govern as one.

Yoon took office when the clock ticked over to start Tuesday as South Korea’s eighth elected president since full democracy in 1987, facing daunting challenges from a Covid-ravaged economy to increasing weapons tests by North Korean leader Kim Jong Un. The conservative must overcome a hostile legislature, a lack of diplomatic experience and historically low popularity for an incoming elected leader in Asia’s fourth-largest economy.

Yoon, who in March squeaked out a victory in the closest presidential race in the country’s history, has called for greater private-sector-led growth, bolstering the nuclear power industry and a tougher approach toward China and North Korea. 

“The Yoon administration must revise and change pretty much all of the South Korean government’s strategic policies, including foreign policy and the policy for North Korea,” said Cheon Seong-whun, a former security strategy secretary for South Korea’s presidential office. 

The 61-year-old Yoon will be inaugurated at a ceremony in Seoul that starts Tuesday at about 11 a.m. He is set to share a stage at the ceremony with Park Geun-hye, a former president he helped send to prison when he was a lawman, and outgoing leader Moon Jae-in, whose progressive ruling party rammed through a prosecutorial reform law in his final days in office that could make it more difficult for the new government to probe possible wrongdoing by its predecessor.

U.S. second gentleman Douglas Emhoff, China’s Vice President Wang Qishan and Japanese Foreign Minister Yoshimasa Hayashi are expected to attend the inauguration ceremony, according to Yoon’s office. 

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While market players have been encouraged about the prospects of Yoon abolishing a capital gains tax planned for next year, surveys show the majority of the public is not sold on him as he embarks on the single-five year term for presidents. Yoon takes office with an approval rating of 41%, according to Gallup Korea, making him the first new elected leader not to hit 50% before taking over. The support rate is also below that of Moon, who leaves with a mark of 45%, it said.

Yoon will quickly be tested with President Joe Biden set to visit Seoul for talks about 10 days after he takes office. The U.S. leader may like what he hears from Yoon, who vowed the major semiconductor-producing country would take part in the Biden administration’s new supply chain initiative, strengthen military cooperation and back the Quad grouping of Australia, India, Japan and the U.S. that is seen as a counter to China’s assertiveness in the region.

“The incoming South Korean administration’s willingness to collaborate more with the United States as well as the Quad could have an impact on non-traditional security issues such as supply chain resilience,” said Naoko Aoki, a nonresident senior fellow at the Atlantic Council.

Aoki added coordination that involves the broader international community may be a challenge due to Russia’s invasion of Ukraine and U.S.-China competition. “It could also be difficult to steer the attention of the United States away from the Ukraine crisis, too, despite North Korea’s frequent missile tests,” she said.

Moon’s feud with Japan over contrition for its 1910-1945 colonial rule over the Korean Peninsula and efforts to court China frustrated U.S. efforts to stitch together a stronger coalition in Asia.  

But gridlock awaits Yoon, with Moon’s Democratic Party holding a supermajority in parliament until at least the next elections in 2024. 

Yoon squandered political capital before taking office with an unpopular decision to immediately move the presidential office from the long-used office and residence known as the Blue House. His government will take it to a part of Seoul where the Defense Ministry is located that also hosted a U.S. military base for decades.

South Korea President Yoon’s Blue House Move Will Reshape Seoul

North Korea’s official media has only mentioned Yoon once, delivering a one-sentence dispatch when Yoon won the March election. But Pyongyang has let him know that a rough ride awaits, after Moon for five years sought rapprochement and was often loathe to punish Pyongyang for its bad behavior. 

Since Yoon’s election, North Korea has been on a pace for its busiest year of missile tests, firing off in March its first intercontinental ballistic missile since 2017 and launching new missiles designed to strike South Korea with an atomic weapon. Meanwhile satellite imagery indicates North Korea is preparing for its first nuclear test in nearly five years.

The North Korean leader signaled he’s ready to use nuclear weapons against South Korea. Kim said at a military parade last month that his arsenal was not only to deter an invasion, but has a “second mission,” warning of a tactical strike “should there be an outbreak of an unwanted situation on this land.”

©2022 Bloomberg L.P.