The party was formed by the notable figures of New Democratic Party and Council for the Promotion of Democracy. Most of NDP politicians including Kim Young-sam and Kim Dae-jung were banned by New Military of Chun Doo-hwan in 1980. There were 2 opposition parties formed at this time ― Democratic Korea Party and National Party of Korea. Nevertheless, both were often regarded as satellite parties of the ruling Democratic Justice Party. Many of the former NDP and CPD members formed New Korea and Democratic Party, in a purpose of the "real opposition", after their political bans were lifted in December 1984. Originally, they intended to re-establish the NDP, but impossible because the name "NDP" was prohibited. Instead, they opted "New Korea and Democratic Party" that can be abbreviated as "New Democratic Party ". The party was officially founded on 18 January 1985, and elected Lee Min-woo as the Chairman.
The party, however, faced the general election on 12 February, shortly after the formation. Due to the short preparation time along with the government's election fraud, the party was expected to be defeated. The Agency for National Security Planning analysed that NKDP would barely win around 20 seats, and in addition, Chairman Lee running for Jongro & Central District of Seoul, would be lost in the constituency. Nevertheless, the party shockingly won in the election, receiving 29.3% and won 67 out of 276 seats, made it as the main opposition in the National Assembly. Furthermore, Lee, who received 31.63%, also won in his constituency. Their seats were later increased up to 103, after some MPs from DKP and Nat'l defected to NKDP, which occurred serious conflicts between the government and the opposition. This, however, also boosted the government's repression that reached its zenith when the party's MP Yoo Sung-hwan was arrested after his parliamentary speech on 14 October 1986.
Decline and dissolution
The party faced an internal conflict after Lee announced his own plan, named "Lee Min-woo Plan", which supported parliamentary system. This was strongly objected by Kim Young-sam and Kim Dae-jung, who advocated to maintain the incumbent presidential system but sought for direct election of the President. Finally, both pro-YS and pro-DJ factions broke the party out and founded United Democratic Party on 21 April 1987. Since 74 MPs defected to UDP, the seats were plummeted up to 26. Although the minor People's Democratic Party merged itself with NKDP in April 1987, the party never revived, and didn't even put a candidate for upcoming presidential election. Lee also resigned his chairmanship and retired from the politics on 6 November. On 15 January 1988, the acting Shin Do-hwan was officially elected as the new Chairman. However, the party lost all seats in 1988 election, and was subsequently deregistered on 28 April.
