SEOUL, South Korea —With its disgraced former leader ousted from office, South Korea’s attention is shifting to a presidential election that could reshape the nation’s policy on North Korea and its relationship to the United States.

Last week’s removal of the country’s conservative president, Park Geun-hye, amid a corruption scandal that has upended the political order could create an opening for liberal parties for the first time in nearly a decade, analysts say.

Recent public opinion polls show that the top two contenders in the May election are from the center-left Democratic Party. Its candidates in some cases differ from the conservatives, in substance and tone, on dealing with the threat of North Korea’s advancing nuclear program and South Korea’s security relationship with Washington, which has been its closest ally.

American and South Korean ideological labels don’t always correlate. In the last decade, the United States — under both Republican and Democratic administrations — has been more aligned with South Korean conservatives than with liberals on North Korea policy.

The conservatives generally favor a tougher stance concerning their neighbor, with principled engagement and pressure on the communist regime. Liberals might seek to revive cross-border ties and seek increased engagement, with fewer or no preconditions.

The polls suggest that support for conservatives has collapsed.

The Park corruption drama prompted millions of frustrated South Koreans to attend massive rallies, energizing the liberal opposition.

The former ruling party is now split over support for its ousted leader, and its prospects dimmed further when two leading figures — former U.N. Secretary-General Ban Ki-moon and the current prime minister and acting president, Hwang Kyo-ahn — decided against a run. Both had been expected to seek the office as a member of a conservative party.

“This election is the liberals’ to lose,” said Bong Youngshik, a research fellow with the Institute for North Korean Studies at Yonsei University in Seoul. “The conservative parties, because of their ties to Park Geun-hye, do not have any strong candidates.”

The conservative disarray creates an opening for former National Assembly member and Democratic Party leader Moon Jae-in, the leading candidate in polls. A former top aide to late President Roh Moo-hyun, Moon was narrowly defeated by Park in 2012.

The election has been set for May 9, the latest date it can be held under the impeachment law, and it feels as though the campaign has already begun. In recent days, Park’s conservative Liberty Korea Party blasted Moon for a willingness to change direction on security.

The barrage of criticism includes Moon’s desire to delay the installation of a U.S.-supplied missile defense system designed to counter North Korea.

The system, THAAD, has angered China so much that it has retaliated economically, blocking tourist groups from visiting and removing South Korean programming from streaming services. Park wanted the system installed by summer, but Moon would prefer to wait for a new government before deciding how to proceed.

The United States has already delivered the hardware.

Other high-profile potential candidates include An Hee-jung, a provincial governor from the Democratic Party who is more moderate on some security issues; Ahn Cheol-soo, a software executive turned National Assembly member from the more liberal People’s Party; and Rep. Yoo Seong-min, a lawmaker from the conservative Righteous Party, which split from the ruling party over Park.

Hwang, the prime minister who is serving as acting head of state in Park’s absence, said he would not run. Other than Hwang, the conservatives have few other candidates who have registered statistically in public opinion polls.

“For the management of the stability of the state and a fair presidential election, I’ve decided that it is inappropriate for me to take part in the election,” Hwang said.

The parties are expected to name their candidates by late March or early April, allowing for a monthlong sprint to the election.

Meanwhile, the national elections commission has expressed concern that the shortened election schedule could allow chicanery to skew the outcome.

It warned in a statement that “false facts, slander, propaganda, voter buying or gift giving will be strictly punished” — and it asked South Koreans to “carefully examine” the candidates and their positions before voting.

Whoever runs, it’s clear that Park will cast a shadow on the race.

State prosecutors announced Wednesday that they summoned the former president to appear March 21 as a criminal suspect in a corruption case. She faces numerous charges, including bribery and abuse of power.

Matt Stiles is a special correspondent.