South Korea’s upcoming June local elections will test whether President Lee Jae Myung can convert his political strength into durable governing power across the country’s regional administrations.

Voters will choose mayors and governors in all 17 metropolitan and provincial jurisdictions on June 3 in the first nationwide electoral contest since Lee took office. The vote will determine control of key administrative and economic centers, including the politically pivotal cities of Seoul and Busan, and is widely viewed as an early referendum on Lee’s first year in office.

The elections will take place alongside several parliamentary by-elections, raising the possibility of