South Korean President Moon Jae-in must win upcoming elections to avoid becoming a lame duck in the second half of his single, five-year term. But first he's got to consolidate power within his own party.

To do that, Moon's looking close to home. Almost 60 former aides and staffers from the presidential office and government are running in primaries that begin Monday — an unprecedentedly large number. Their success or failure will shape the ruling Democratic Party of Korea's fortunes on April 15, when all 300 National Assembly seats are up for grabs.

While midterm elections are important to presidents the world over, they're particularly high stakes for South Korean leaders, who have a history of getting bogged down by corruption scandals after defeats at the polls. Getting more trusted aides — known as "knights" — into parliament could also help Moon avoid the past pattern of ruling party lawmakers breaking with presidents as their terms wind down. There's already been signs of dissent with the ranks.