Dan Janison Melville. N.Y. Tuesday January 26, 2010. Daniel Janison,

Dan Janison has been a columnist at Newsday since 2007.

The published leak of Donald Trump’s 1995 tax return has dominated campaign coverage since Sunday. Notably, the Trump camp has not challenged its authenticity, even while complaining about how The New York Times presented it and threatening legal action.

Gov. Chris Christie and ex-mayor Rudy Giuliani — who built reputations as prosecutors — act these days as if they’re defense lawyers for Trump in the court of public opinion.

They’re trying to make the best of the case they’ve been dealt. As such, both argued that Trump’s strategies, entirely legal, show his genius as a businessman, even if taking tax advantage from a loss is said to be common in real estate.

If a massive loss meant he could avoid paying income taxes for many years, the argument goes, then Trump merely followed laws the politicians put in place.

But the kind of attention now paid to this apparently involuntary disclosure could damage Trump for several reasons.

For one, the suggestion that he avoided payment will not sit well with some who believe the economic system is rigged and decline to applaud crafty big shots who come up winners.

advertisement | advertise on newsday

Hillary Clinton was all set with an ad meant to take advantage. Trump showed, it claimed, that he is “completely comfortable with paying zero dollars to support our troops, schools, veterans, and health care system.”

“If not paying taxes makes him smart, what does that make the rest of us?” she has said on the campaign trail.

The leak also highlights the fact that he has to date refused to release returns, a contrast to other major-party presidential candidates for four decades.

Any focus on Trump’s businesses highlights anew a long negative narrative, most recently from Clinton, that he stiffed contractors, peddled a dubious “university” and said 10 years ago that he hoped for a housing collapse.

But the tax leak’s worst sting for the billionaire may be that his enemies can shape it to portray him as a failure. He declared a $916 million loss. There were bankruptcies tied to busted casinos. There was the purchase of the Plaza hotel, which he later had to give up.

All this allows Clinton — for the moment — to divert attention from Trump’s argument that she’s the real failure in the race.

She gains the context to dissect his business record without having to defend U.S. policy in the Obama administration where she was secretary of state, or her email practices, or potential Clinton Foundation conflicts.

In sum, she gets to play momentary offense without much resistance.

advertisement | advertise on newsday

Clinton’s upper hand in the public-relations war might not last, though time is wasting for Trump to regain it with just over a month left to Election Day.

Given the way the rest of the race has gone, no reversal of fortune should come as a surprise.