Former Conservative Party leader Colin Craig will face a second trial on claims he defamed Taxpayers' Union founder Jordan Williams.
A Supreme Court decision, released today, is the latest development in the long-running legal saga.
After a four-week trial in 2016, a High Court jury found Mr Craig had defamed Mr Williams at a news conference and in a leaflet distributed to 1.6 million households in July 2015.
The jury awarded damages of almost $1.3 million dollars to Mr Williams - the highest ever for a defamation case.
However, a subsequent review of the result by the trial judge found the amount was excessive and constituted a miscarriage of justice. Because of that, the jury's verdict was set aside and a retrial ordered.
That sparked appeals from both sides, which eventually found their way to the Supreme Court.
In the judgment released today, the Supreme Court - by a majority - ordered a retrial on the defamation claim and the damages awarded.
The court action is one of a number of legal proceedings launched in relation to the fallout from the 2014 election campaign and the sudden resignation of Mr Craig's press secretary, Rachel MacGregor.
Mr Craig also sued Whale Oil blogger Cameron Slater for defamation, as well as Ms MacGregor herself.