The second call came as she realised there was no way she'd get a tax on capital gains across the line, and if she pressed ahead with it, there'd be a mutiny.
Leading it would most certainly have been Winston Peters who has said right from the start we already have a capital gains tax, the bright- line test which taxes rental properties if they're sold within five years of purchase.
Left flailing around in the swirling political maelstrom is the Greens co-leader James Shaw who once said the Government doesn't deserve to be re-elected if it doesn't introduce the tax on capital.
Now he's lamely saying he'd prefer to work with this Government than a National one.
And struggling to keep his head above the Beehive's wake is Simon Bridges who has now lost his only tub thumping cause.
The only tub he'll be thumping now is the one in his caucus room the week after next as he struggles to keep his captain's stripes.
The lead-up to what is a colossal back down by Labour was a schmozzle, not all that unusual for this administration.
Their two associate Finance Ministers, one of them Stuart Nash whose in charge of revenue and the other David Parker, seemed out of the loop or were simply clumsy in trying to quell speculation that a decision was imminent.
Yesterday Nash, in his regular weekly slot with Newstalkzb, repeatedly said there'd be a decision at the end of the month and it was only the 17th.
And Parker said Cabinet may have discussed it on Monday but there were no decisions.
But James Shaw said he received a call from Ardern one night last week to give him the bad news.
At the end of it Ardern described herself as a pragmatic idealist which is something of an oxymoron.
Still to back away from the capital gains tax, and the promise by Ardern never to promote it again, and despite the political capital that has been sacrificed on the way, the decision is for Labour the only one it could have taken.
The alternative was to effectively have tax as a referendum at the next election, and Labour should know by now, that's a sure fire loser.
The only one left feeling smug at the end of all of this is the Admiral of the fleet, Winston Peters.