A ruling Saenuri Party supporter in a red wig waves the national flag during parliamentary election campaigning. The elections will select a total of 300 lawmakers across the country on April 11. (Kim Kyung-Hoon/Reuters)

South Korea’s two largest political parties have both tried recently to reinvent themselves. The liberal party merged with a smaller faction, changed its name and revamped its leadership. The ruling conservative party came up with a name change of its own, promised an end to corruption scandals and vowed to “earn the public trust.”

The rebranding attempts played to widespread voter concerns about the political crookedness — rampant cronyism, bribery and, more recently, tightening controls on speech freedom — in a young democracy that sometimes still resembles the military dictatorship of three decades ago. It also reflected the mounting disapproval with President Lee Myung-bak, whose corporation-friendly economic policies, critics say, have widened the gap between the rich and poor.

But in advance of Wednesday’s parliamentary elections, both of South Korea’s major parties, beset by fresh controversies, have squandered the sense that they are offering something new, pundits say.

The quadrennial race to claim a majority in the 300-member National Assembly — and to gain momentum for December’s presidential election — was supposed to be a referendum on South Korea’s hot-button domestic issues, including education costs and access to welfare. Opinion polls suggested that those social and economic issues, far more than the issue of Seoul’s policy toward its authoritarian neighbor to the north, would determine the election. Both new parties, in recent months, shifted their platforms slightly to the left to capitalize on that sentiment.

Instead, the April campaign season has been driven by two scandals— one that started with a YouTube clip and one that took off because of the files on a computer memory stick. And a too-close-to-call race might be decided, analysts say, by which party better succeeds at damage control.

Both parties have said they want more engagement with North Korea, the difference only in degree. When Lee took office in 2008, he reversed the pro-engagement policy of his liberal predecessors, pulling away many of the aid packages and conditioning their return on Pyongyang’s denuclearization. North Korea has since conducted a series of missile launches, nuclear tests and military attacks, and relations between the Koreas remain testy.

The North frequently describes Lee as a traitor and a sycophant to Washington. On Tuesday, North Korea’s state-run newspaper asked South Korean voters to “punish the conservatives who are trampling down democracy and human rights.”

The YouTube clip begat the more recent, and more minor, scandal. It documented the vulgar comments of opposition Democratic United Party (DUP) candidate Kim Yong-min, a popular shock-jock podcaster, who joked eight years ago about carrying out a terrorist attack on the United States and releasing a serial killer to sexually assault then-U.S. Secretary of State Condoleezza Rice. The politician also suggested that the serial killer should attack then-Defense Secretary Donald H. Rumsfeld and President George W. Bush. Since the YouTube clip was posted, senior officials in Kim’s party have begged him to resign. Kim has refused.

“Kim Yong-min’s scandal exploded at the end of the campaign, so there has been no time for the party to come up with [a defensive] strategy,” independent political commentator Ko Sung-kook said.

Kim’s comments — and his persistence to stay in the race — have stolen some of the attention from the broader scandal, which blew up last month when a group of striking workers from the Korean Broadcasting System received a memory stick from a government whistleblower.

The memory stick, it turned out, contained thousands of documents detailing a government surveillance operation that included phone-tapping and spying on journalists, activists and opposition politicians. Media outlets in Seoul quickly described the scandal as a Korean Watergate, and opposition politicians demanded that President Lee make clear whether he knew about the operation — something he hasn’t done.

The scandal has left both parties scrambling, though. The ruling Saenuri Party, previously known as the Grand National Party, has tried to distance itself from the unpopular president by calling the scandal “unimaginable” and asking for a public apology from the presidential office.

The presidential office, meanwhile, says that 80 percent of the disclosed surveillance cases were conducted by the previous administration of liberal president Roh Moo-hyun. That has forced the current generation of DUP leaders, some with ties to Roh, to defend themselves. DUP candidate Moon Jae-in, who served as a chief of staff for the Roh administration, said on Twitter that surveillance “during the Roh leadership was to inspect public offices” — not private citizens.

The Saenuri Party “had more risks at the outset of the campaign with Lee Myung-bak’s unpopularity and surveillance scandal,” political analyst Kim Jong-bae said. “But [Saenuri leader] Park Geun-hye has drawn a line between her and Lee and successfully removed Lee’s shadow.”

The latest poll conducted by the Korea Society Opinion Institute indicated a tight race, with 39 percent support for the Saenuri Party and 34 percent for the DUP. Analysts say the race could swing on voter turnout, with young people overwhelmingly favoring the DUP.

Special correspondent Yoonjung Seo contributed to this report.