In his campaign to become South Korea's president, Moon Jae-in touted his credentials as a human-rights lawyer and pledged to enforce a strict moral code in picking his top officials.

Now, two months after being sworn in, Moon's own standards are making it hard for him fill his Cabinet.

Four of the 18 berths are still occupied by officials from the prior administration of ex-President Park Geun-hye. Discussions on three nominations are underway, but the opposition is resisting two of his picks — for defense minister and labor minister — citing concern about their records. While parliamentary approval isn't required, Moon needs the opposition on board. Otherwise he could risk his economic reforms being stalled in a legislature he doesn't control.