(CNN)On Tuesday, in a building along the border between North and South Korea, negotiators will sit down face to face for the first time in more than two years.
Ministry with 'intractable' task of reuniting North and South Korea
That meeting, the latest in a flurry of rapprochement between the two sides, comes after a breakthrough call between Seoul and Pyongyang last week.
At the South Korean end, were two employees of the Unification Ministry, patiently calling North Korea every day at 9 a.m. and 4 p.m., and never once receiving an answer.
The welcome break in tensions that have been building on the peninsula amid North Korean weapons testing and saber-rattling rhetoric from Washington, has thrown a spotlight onto the ministry, normally little noticed outside Korea, giving its mission new purpose and importance within President Moon Jae-in's foreign policy.
But despite its growing prominence, reunification of the two Koreas faces almost insurmountable problems, analysts say, and little support among a younger generation that has never known a unified Korean Peninsula.
Based in an imposing, boxy government building on a tree-lined street near Gwanghwamun Square in central Seoul, the Unification Ministry is "responsible for all issues pertaining to inter-Korean relations and unification," according to its official website.
This rather bland mission statement masks a sprawling ministry with hundreds of employees and units dedicated to military analysis, negotiations and dialog with North Korea, economic exchanges, and refugee support.
The Unification Ministry was deeply involved in arranging talks between the two Koreas and joint economic projects like the Kaesong Industrial Park.
According to the Yonhap news agency, the ministry's budget for 2017 was $1.02 billion, down 20.5% on the year before, a drop ministers put down to worsened ties between the two Koreas in the last year of the conservative President Park Geun-hye administration.
Support for the ministry has fluctuated as political moods have shifted in South Korea. Under Park's equally conservative predecessor, Lee Myung-bak, it was even "on the chopping block," according to a leaked 2009 US government cable.
"(The ministry) survived, largely because progressive forces came to its defense," wrote US diplomat William Stanton, but key liberal officials were fired, staff cut, and it was moved from a standalone building to offices within a larger complex.
The ministry was founded in 1969 as the National Unification Board, "a government body responsible for all issues pertaining to inter-Korean relations and unification," according to its official website.
This was a period of high tension on the Korean Peninsula. The year before, North Korean commandos had infiltrated Seoul with the intention of assassinating President Park Chung-hee. They came within 100 meters of the Blue House before they were detected and most were killed in a massive gunfight with South Korean guards.
In the year running up to that incident, the US estimated hundreds of North Korean guerillas had crossed the DMZ, and, as South Korean officials told their US counterparts at the time, the feeling in Seoul was North Korean leader Kim Il Sung had shifted "from peaceful unification to the use of force to achieve unification."
While Park's government attempted to reassure its allies it was committed to peaceful reunification, the strongman leader -- who had seized power in a military coup in 1961 -- was widely viewed as unpredictable and hotheaded, and many in Washington feared he was just as likely to spark a second Korean War as Kim.
Despite this, in 1972 both Koreas, after intense negotiations, issued a joint statement laying out their commitment to a peaceful, non-military reunification of the peninsula "without depending on foreign powers and without foreign interference."
According to Shin Jong-dae, a professor at Seoul's University of North Korean Studies, this was the first document agreed on by both Pyongyang and Seoul since the division of the peninsula in 1945.
It also established the hotline between the two countries, which, apart from a brief four year interlude between 1980 and 1984, was in regular use until it was cut off in February 2016.
While relations between North and South Korea have waxed and waned considerably in the intervening period -- declassified cables show North Korea considering unification by force again within years of the joint declaration -- the importance of the communication system set up and the work of the Unification Ministry is evidenced by the sudden breakthrough this month.
A landmark agreement signed by the leaders of both North and South Korea during a period of improved ties in 2000, hinted towards a possible future federalized state, with little indication how this would be achieved.
The agreement tied both countries to "promoting balanced development of the national economy through economic cooperation and by stimulating cooperation and exchanges in civic, cultural, sports, health, environmental and all other fields."
Anwita Basu, an analyst at the Economist Intelligence Unit (EIU), said this could involve "staged reunification," whereby the North "operates as an autonomous region under the overarching governance of the Southern government," but she warned this was incredibly unlikely at the present time, as "North Korea dismisses South Korea as a legitimate state."
"The two Koreas fundamental ideological difference make it difficult to conceive a credible reunification strategy," she added. "Each want to bring the other under its umbrella and government which frankly is intractable."
There are scant examples of peaceful reunification, particularly of such different countries.
In 1990, the Federal Republic of Germany absorbed East Germany and became one country again. While this was a much welcomed and peaceful process, it followed dramatic upheaval and revolution in East Germany which left the government there on the brink of collapse.
The cost of reunification was massive, estimated at upwards of $100 billion a year in the two decades after 1990, and today GDP, unemployment and other economic indicators show former East German states lagging behind their Western counterparts.
Another possible model is that of Hong Kong, control of which was handed over from the UK to China in 1997, establishing the principle of "one country, two systems," by which Hong Kong retained its political and economic models, but sovereignty and ultimate control passed to China.
This was once mooted as a potential model for reuniting Taiwan and China, which split at the end of the Chinese Civil War in 1949, but in recent years, "one country, two systems" has come under increasing strain, with support for it in Hong Kong falling amid Chinese encroachment and shrinking political freedoms.
Either of the above models would require colossal political change in North Korea, currently one of the world's most autocratic countries, ruled by the third-generation of the Kim family which has been in control since the end of World War II.
"At this stage, reunification is a very remote prospect," said Basu, the EIU analyst.
It's difficult to imagine Kim Jong Un giving up control and allowing his country to be absorbed into South Korea, even with a high degree of autonomy. Nor are South Korea's 51 million people likely to vote to become part of a Kim-ruled united Korea.
A more likely scenario for unification is political collapse in North Korea, brought on by revolution, a military coup, assassination of Kim, or war with South Korea or the United States.
Estimates of the cost of reunification to South Korea range from around $500 billion to several trillion dollars, comparable to the amount spent by Germany since 1990.
Modeling the economic costs is incredibly difficult however, as this would be a completely unique event, potentially catalyzed by violent upheaval inside North Korea and the creation of hundreds of thousands of refugees.
"The differences between the economies of North and South Korea are much greater than were those between East and West Germany," wrote academics Sangmin Bae and Martyn de Bruyn in 2010, pointing to South Korea's far greater population, GDP and quality of life.
"This could lead to massive migration (to South Korea)," they said. "To be sure, the relative costs of unification in Korea would be even higher than the enormous costs in Germany."
Moreover, "unlike the Germans, the Koreans fought a bloody civil war," leaving deep wounds on both sides of the border that could act as a major barrier towards reunification and integration of North Koreans into a South Korean-led country, Bae and de Bruyn said.
A more pressing concern, would be the simple integration of North Koreans into South Korea's highly complex economic system said Basu: "The newly created country (would) struggle to find a unified national identity ... Even today North Korean defectors find it very difficult to integrate into South Korean society. More often than not they are treated poorly and discriminated against."
A Council on Foreign Relations report warned last year a unified Korea "could become a constant source of instability or a country preoccupied with internal problems."
These difficulties, as well as years of North Korean aggression, could explain why South Koreans, particularly younger generations, are less supportive of unification than in the past.