John Armstrong: Extremely important, or acutely foolish

Trevor Mallard had better be right - for his and Labour's sake.

Coming on the day the party said it was refocusing its billboard adverts on Don Brash's trustworthiness, Labour will see its credibility sapped unless it backs up Mr Mallard's assertion the National leader is in the pocket of Americans.

If it is true that Dr Brash is at the beck and call of Washington in exchange for Americans bankrolling National's election campaign, then he will be obliged to quit as leader as a bare minimum.

If not, then Mr Mallard's insinuation - made out of the blue yesterday during a press conference on National's new student loan policy - is a smear tactic of the ugliest and most desperate kind. The voters will judge accordingly - and not in Labour's favour.

Unsubstantiated allegations surrounding the source and motives of party donations are nothing new. But amid the murk, some of the mud inevitably sticks. And more than likely, this is how things will end up in this latest example.

This time, however, the claims carry extremely serious overtones because Mr Mallard alleges foreign interference in domestic politics. The implication is that National is so venal it would surrender our anti-nuclear policy and send troops to Iraq for cash.

So far, all Mr Mallard has supplied as evidence is a Herald story suggesting a wealthy American has made a big donation to National, plus old quotes from Dr Brash declaring a National government would align NZ more closely to Washington.

However, the onus is on Mr Mallard to come up with some truly incriminating links between National Party donors and the US Administration.

Mr Mallard was yesterday unwilling to reveal more until the "appropriate time" - whenever that may be. But then it suits Labour to leave the stench of allegation hanging in the air.

One option for National is to keep the pressure on him to put up or shut up and turn this into an issue of Labour's credibility.

Equally, National may prefer to let the matter drop, conscious that any mention of Iraq or the nuclear policy will remind voters of Dr Brash's seeming reluctance to offer up National's position.

The other question is whether Mr Mallard departed from Labour's script yesterday.

Other Labour figures have been quietly dropping hints about the nationality of some of those making big donations to National within earshot of journalists.

However, judging from the dismay in some quarters, Mr Mallard's effusiveness was not part of the plan.

His contribution coincided with strategists tearing up Labour's limp series of billboard ads in favour of new ones which seek to capitalise on Dr Brash's evasive replies to questions about sending troops to Iraq.

The risk now is that Mr Mallard's allegations could not only backfire on him, they could undermine the message on Labour's new billboards before they have even seen the light of day.