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

Dan Janison has been a reporter at Newsday since 1997.

Under the law, super PACs supposedly operate apart from campaigns, justifying the unrestricted amounts of money they can collect from donors.

But the very names of these entities — as well as the makeup of some of their staffs — reflect what’s widely assumed to be the real game.

Priorities USA Action, for example, is known without contradiction to be a “pro-Clinton” PAC that issued a slick ad attacking Trump for mocking a disabled reporter.

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On the other side, the Make America Great Again PAC is obviously a pro-Trump outfit. It ran broadcast spots during the New York primary of the candidate at his rallies whacking his rivals, set to rousing music.

Election law experts have been parsing the super PAC phenomenon ever since the U.S. Supreme Court’s landmark Citizens United decision in 2010.

This is the second presidential election since the ruling.

But there are key differences this time.

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Many Republicans are clearly nervous this time about their nominee-to-be. And some Democrats, while seeing a need to keep the White House away from Trump, do not especially love their banner bearer-to-be, Hillary Clinton.

So could we see a PAC go rogue this time?

Since it must stay independent under the law, a candidate cannot officially order it to be reined in if it does start marching in its own direction, according to election experts, including New York lawyer Jerry Goldfeder.

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At least in theory, that poses the possibility of a “runaway PAC” — along the lines of a “runaway grand jury” that on rare occasions defies prosecutors and crafts its own course.

If Trump looks out on the landscape, he can see a couple of his former critics running PACs declared to be backing him.

Veteran GOP operative Alex Castellanos said on CNN less than a year ago of Trump’s immigration plan, “If you think the Republican Party hasn’t alienated enough Hispanics, enough women, enough young voters, [the plan] is going to be great for you.” He even suggested the policy conflicted with the Constitution.

But now Castellanos, who advised Mitt Romney in 2008, told The New York Times he’s advising the purportedly pro-Trump group Rebuilding America Now, on countering Clinton’s advertising.

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Then there’s Ed Rollins, a senior presidential fellow at Hofstra University who’s among the many Republican stalwarts to have expressed the view that Trump is a narcissist.

Rollins is now co-chairman of the Great America PAC. Rollins said in a memo cited by The Wall Street Journal last month that the group has raised more than $2 million on Trump’s behalf and built him an “army” of active supporters.

On the Democratic side, Newsday reported Wednesday that Jon Cooper, the former Suffolk County legislator and major fundraiser for President Barack Obama, is chairing a new super PAC devoted to defeating Trump. But unlike Priorities USA, it won’t be promoting Clinton.

“I thought there was a need for a home for Hillary supporters, [Sen.] Bernie [Sanders] supporters and disaffected Republicans to make sure Donald Trump does not become the next president,” Cooper told Newsday’s Tom Brune.

Such distinctions among PACs make you wonder what might happen if either Clinton or Trump tanks so badly in polls before Election Day that the election seems predestined weeks or months before it is held.

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Theoretically, those in charge of an independent PAC could cut bait if they wish and focus on down-ballot races to protect House members and senators of either party.

Nobody has said they would — but they could.

Perhaps that is at the back of some minds in an unpredictable election year.