His party members were already choking on free market economic reforms they had never imagined a Labour Government would adopt. A compromise on the party's long-standing opposition to nuclear power and Anzus was not on.
When the cabinet refused to accept the Buchanan, the US and Australia declared their alliance with New Zealand "suspended". The US froze New Zealand forces out of future military exercises and made Lange unwelcome in Washington.
The American reaction turned public opinion in New Zealand strongly behind the anti-nuclear policy. By the time legislation was passed in 1987, establishing the nuclear ban in law, New Zealanders regarded it as a test of their right to make the decision.
Anti-nuclear protesters had come a long way from flotillas on the Waitemata against visiting US warships. With the help of clumsy US diplomacy they made nuclear freedom an issue of national pride that future Governments dared not change.
Both countries soon recognised their alliance could never be revived but with the passage of time, and military efforts in Afghanistan, the rift is healing.
New Zealand prime ministers are now welcomed at the White House and its forces are slowly regaining invitations to joint exercises. The country has proved its sovereignty to itself.
What are your memories of the 1984 nuclear standoff? Leave your comments below