By Andy Jackson

There are two big stories from last week's by-elections. The first has been widely reported but the second has slipped under the radar.

The first story is that the party in power has once again lost a by-election. The majority Grand National Party thought that they were ready to break that trend and win at least three out of the five contests last week but ended up winning only two. The Democratic Party swept the ``swing districts" in Ansan and Suwon in Gyeonggi Province.

There were several factors that led to the GNP's defeat.

First, although the party remains more popular than its chief rival (36 percent to 29 percent in the latest poll by Realmeter), there is a tendency for supporters of the party out of power to be more motivated to come out and vote. That is especially true in by-elections, which tend to have relatively light turnouts.

Second, while the GNP is more popular than its rival, it still has nowhere near majority support. In a by-election like this, the majority party has to beat the ``not GNP" vote as much as they have to beat the Democrats. It clearly failed to get over that hurdle last week.

Also, the GNP still has issues with candidate nominations. In Ansan, the GNP's Song Jin-seop was a nice enough guy, but he was overwhelmed by Democrat Kim Young-hwan, a political heavyweight who had previously been a lawmaker and science minister under Kim Dae-jung.

While we are on the subject of poor nominations, is there any reason for the race in Yangsan, South Gyeongsang Province to have been the closest race of the day? The GNP nominee, Park Hee-tae, has had a long and storied political career, having served as party chairman and vice National Assembly speaker, but the 71-year old was hard-pressed against an aggressive challenger in what should have been a relatively safe race. By-elections are no place for giving out laurels to party warriors at the end of their careers. You save that for the proportional representation party list in the regular elections.

In the GNP's defense, they are a victim of their own success. Most of their first-tier political figures have already been elected to office in the 2006 local elections and the 2008 National Assembly races. On the other hand, the Democrats have people like Kim and former Roh Moo-hyun administration secretary Song In-bae (who ran in Yangsan) available.

Finally and in the ``what can you do" category, you have what happened in Suwon. The majority party had a strong enough candidate in former broadcaster Park Chan-sook, who had an early advantage in the polls. Alas for the GNP, Suwon is the political base of former Gyeonggi Province governor and United Democratic Party chairman Sohn Hak-kyu. Sohn is still popular in Suwon and essentially spent the entire campaign period camped out in the city stumping for Democratic Party candidate Lee Chan-ryul block by block. With Sohn's help, Lee camp from behind to prevail.

(Look for Sohn to move up in the ranks of likely Democratic nominees for president in 2012.)

The Democrats' victory deservedly got most of the attention, but another important development was the absence of any serious third-party or independent candidates in the mix. The only place where a candidate outside of the GNP or DP got second place was in Gangneung, Gangwon Province, and that was only because the DP did not bother to field a candidate in the district.

Although the GNP cannot be happy with last week's results, they are actually an improvement over last April's by-election, when the party was shut out in all five National Assembly races. In that election, independents took three seats and the DP got one while the minor New Progressive Party picked up its first seat.

In fairness to the major parties, those three independents actually represented dissatisfied factions of those parties, but the fact that they could run as independents and defeat their parties' nominees is telling.

In that same election last April, both the GNP and DP were shut out in competitive local by-elections in their respective political bases in the southeast and southwest.

The two parties' improved performance is natural since their combined share of popular support has risen from 41 percent to 66 percent over the past four months based on polling from Realmeter.

What is driving the increased dominance of the big two?

In single-member district systems like you find in most Korean elections, there is a tendency for two relatively moderate major parties, one center-left and the other center-right, to develop (Google ``Duverger's law"). So, in the absence of a compelling reason to potentially ``waste" a vote on a minor party or independent candidate, voters will generally limit their choice to one of the two largest parties.

That ``compelling reason" has been largely removed because both parties have gotten a little better about not turning the public off with their behavior. Over the past few months, we have seen relatively little of the floor-fighting and street protests that we are used to seeing.

(Relatively) good behavior has its rewards.

Andy Jackson has taught courses on American government and has been writing on Korean politics and other issues for four years. He is the chairman of Republicans Abroad-Korea. He can be reached at andyinrok@lycos.co.