South Koreans head to the polls Thursday to elect members of the country's parliament, known as the National Assembly. This year's election is dominated by the impeachment of the country's president. Candidates also are having to tough new campaign laws meant to clean up government.

For the first time, South Korean voters are electing a National Assembly in the shadow of an impeached president. While there are more than a thousand candidates from about a dozen parties, the impeachment has become a key issue between the two main parties in contention.

Many South Koreans say the conservative Grand National Party, of GNP, went too far last month when it drove the impeachment of President Roh Moo-hyun through the legislature last month. The president is now waiting for a court ruling on whether he will be permanently removed from office.

The reform-oriented Uri Party, which is allied with Mr. Roh, exploited that anger in its campaign. And as late as last week, pollsters predicted a voter backlash would produce a sweep for Uri, and for Mr. Roh's vision of clean government.

Scott Snyder, of the Asia Foundation in Seoul, says those predictions have faded and there are signs of a much tighter race. "The opposition party has now recovered a lot of ground by essentially warning against an overreaction that would give all the power to the ruling party," he say.

The GNP also is campaigning with a message of renewal. It says it has reformed after decades of funding scandals and allegations of corruption.

At a crowded rally, GNP Chairwoman Park Geun-hye tells supporters the party is committing to clean and correct government.

The GNP also got a boost from a high-profile blunder by Uri Party Chairman Chung Dong-young. Mr. Chung resigned his post and went on a hunger strike this week to apologize for saying that elderly voters should "stay home and rest" on election day. The Uri Party gets most of its support from younger voters.

Uri Party candidate Yoo Jye-gun says Mr. Chung's comments were a mistake. He admits it has probably galvanized older voters, who traditionally support the opposition GNP. "I presumably, reasonably believe that elderly people will turn out more than younger people," he says. "I personally hope that younger people should come more, but I don't know."

One of Mr. Yoo's campaign stops illustrates how the style of South Korean campaigning has changed this year. A handful of supporters applaud Mr. Yoo as he addresses them from a tiny sound truck on a busy street corner.

Stringent new rules by South Korea's National Election Commission now forbid previously routine practices, such as paying supporters to attend rallies, or putting out large spreads of food and drink.

As a result, many candidates are emphasizing personal contact with smaller groups of voters. At one GNP rally, a candidate entertained supporters by singing and playing guitar.

Tami Overby is the executive director of the American Chamber of Commerce in Seoul. She says she recently discussed the new election rules with the chairman of one of South Korea's chaebols, or family-owned conglomerates. "I asked him how it was different. He said normally, before an election his phone would not stop ringing. And it would be candidates asking for money," she says. "This time his phone has not rung at all."

Both major South Korean parties say they will carry the banner of clean, transparent government forward. Thursday's polling will reveal which party voters believe - and whether the vows to end corruption will last beyond election day.