An atmosphere of suspicion has reasserted itself on both sides of the border
As tensions continue to escalate between North and South Korea, the BBC's Korea correspondent, John Sudworth, looks at the likely outcome for the divided peninsula.
Little more than a year ago an extraordinary journey was beamed live to television sets around the world.
The then South Korean president, Roh Moo-hyun, was in a car heading towards one of the most potent symbols of Cold War hostility, his country's land border with North Korea.
On reaching the Military Demarcation Line, Mr Roh stepped out of the motorcade and walked across, a gesture of reconciliation that once would have seemed impossible.
Back in the car, a couple of hours later, his convoy was sweeping through the streets of the northern capital, Pyongyang, cheered on by thousands of pompom-waving citizens.
Up ahead the North Korean leader Kim Jong-il was waiting to greet him.
That summit meeting, only the second time in history that the leaders of North and South have met, now seems a very long time ago.
North Korea's latest assessment of South Korea's current president and his political allies is far from friendly.
"The group of traitors has already reduced all the agreements reached between the North and the South in the past to dead documents," said a statement carried by the country's official news agency.
Relations have reached "the brink of war" it goes on to say, therefore the North no longer considers itself bound by such agreements.
So what has gone wrong?
South Korea's conservative president, Lee Myung-bak, took office last February insisting that there would be no further unconditional economic aid for the North.
He also said further co-operation would depend on Pyongyang's willingness to give up its nuclear weapons.
TROUBLESOME SEA BORDER
Known as Northern Limit Line
Position in Yellow Sea declared by UN in 1953
Not recognised by North
Deadly naval skirmishes along the line in 1999 and 2002
Regularly breached by North's fishermen
That policy has infuriated North Korea, which believes that strategic issues should be kept separate from the fledgling business and tourism links that were being carefully developed across the heavily fortified border.
So step by step, it has been unravelling those ties.
All cross-border tourism projects have been halted and regular government-to-government contact has been suspended.
Only the joint industrial zone near the North Korean city of Kaesong remains.
The factories there have been built using South Korean investment and are staffed with North Korean labour.
The zone earns the North millions of dollars in badly needed foreign currency, but although reluctant to bite off the hand that feeds it, the chill in relations is still in evidence.
Tighter border restrictions now mean that far fewer South Korean managers are allowed to travel to Kaesong, and the freight train link with the South has been cut.
'Puppet war hawks'
North Korea has been turning up the diplomatic heat.
A senior army official recently made an unusual appearance on state TV, threatening to wipe out what he called "the puppet war hawks in the South".
There is growing concern that such words may eventually be accompanied by the possibility of violent action, perhaps a repeat of the small-scale military skirmishes that have taken place as recently as 2002.
The North Korean claim that it is no longer bound by previous agreements includes specific mention of those relating to its sea border with the South, a long-disputed boundary off the west coast.
Lt Cmdr Yoon Young-ha was one of six South Korean sailors who died in the most recent gun battle with the North Korean navy.
His father, 67-year-old Yoon Doo-ho, is concerned about the possibility of a repeat of such clashes.
"Already too many people have died," he said. "I'm certain that the South Korean government will not let the North Koreans cross the sea-border ever again.
"If it does happen I hope our navy will smash them to pieces."
But blistering rhetorical outbursts are something of a North Korean trademark.
Many analysts believe that it uses them for diplomatic effect, when the need arises, to ratchet up political tension and give itself a stronger hand in international negotiations.
It may be no coincidence that the recent rise in hostility coincides with the arrival of a new administration in Washington.
The South Korean government says it has detected no unusual military activity north of the border.
"We hope that instead of threats of this kind, North Korea would come out to talk to us on matters of mutual concern and interest," Prime Minister Han Seung-soo told reporters.
But for the moment a return to dialogue and the heady days of handshakes across the border looks unlikely.
Plenty of people, including the North of course, are ready to point the finger of blame at the South Korean president.
But for some of his conservative supporters, there is a sense of vindication.
They have long argued that handshakes with North Korea mean nothing, and the optimism that it would change its ways was always misplaced.