There’s an adage in my business that it’s not news when a dog bites a man, only when a man bites a dog.

By that reasoning, the political story of the year so far is Paul Ryan’s announcement that he will not run for president.

Seemingly everyone else in his party will. Rick Santorum’s back. George Pataki’s back. Mike Huckabee’s back, with an alliterative new book (“God, Guns, Grits and Gravy”) that sounds like an agenda hijacked by a Denny’s menu, or maybe a sequel to “Fried Green Tomatoes” starring Mel Gibson and a howitzer.

Even Rick Perry’s back. I’d tick off three reasons that he’s crazy to try again except that I can remember only two. He’s a whole new candidate, at least on the accessories front. It’s been said that Americans give you 10 additional IQ points if you have a British accent; he’s betting on an extra five for eyeglasses.

And now - the heart quickens and the flesh quivers - Mitt Romney’s back. That’s the word this week: that he’s inching ever closer to another presidential bid, which we know because he’s articulated as much to donors.

Doesn’t it pretty much say everything about our political process right now that candidates flag their intentions first to the people they’ll be hitting up for money? And that the way they attempt to clear the field isn’t with a surge in polls but with a fortune in the bank? I bet some of them form PACs before they bother to tell their spouses what’s up. It’s called priorities.

By one count that I just came across, there are 25 Republicans of some standing who have signaled at least a flickering interest in the 2016 race. This certainly explains the dip in unemployment. Thousands of Republican presidential strategists and advisers have been added to payrolls.

It also explains the difference between the parties. Democrats want to expand government. Republicans want to expand auditions for it.

A Romney candidacy would be curious in the extreme. In 2000, Al Gore beat George W. Bush in the popular vote and lost the presidency by dint of a Supreme Court ruling; he nonetheless let someone else carry the Democratic banner in 2004.

That person was John Kerry, who came closer to winning than Romney did, and yet he, too, didn’t circle back four years later for more punishment.

From what I hear, Romney began mulling a third bid for the presidency months ago, when the Republican establishment remained skeptical of Chris Christie and when it wasn’t at all certain that Jeb Bush would join the race. Romney was poised to rush in like a cinematically coifed superhero and save the party from the deliriums of Rand Paul and the diatribes of Ted Cruz.

By the time Bush began all the maneuvering of the last four weeks, Romney had developed the itch. He also apparently believes that Bush’s support for Common Core educational standards and immigration reform will cripple him in the primaries.

If Bush formalizes a candidacy and Romney follows suit, he’d run to Bush’s right. But Bush is the one with the truly conservative record as a governor, in Florida, while Romney is the one with a moderate record from Massachusetts. He’d be flipping the script, and if his political orientation was confusing last time around, it would be only more so this time.

He’s reportedly concerned that Bush’s financial dealings will make him acutely vulnerable to attacks. So the solution is ... Romney?

His campaign would be predicated on buyer’s remorse: Voters could have had him and now get a do-over. But the buyers may be growing less remorseful. Romney had promised them that by the end of his first term, unemployment would be at or under 6 percent. It’s there already, in half the time.

Romney, Perry and others forget that when they’re not candidates, they’re well loved. When they are, they’re well trashed. Today’s fascination is tomorrow’s flop on “Meet the Press,” a hapless porterhouse for the panel to carve up.

Some Republicans (and Democrats) are simply chasing higher speaking fees, maybe a book like Huckabee’s, hold the gravy.

But there’s a cost to us. An overcrowded field of candidates doesn’t mean a more spirited exchange of ideas; it means so many voices that none get properly heard (or vetted).

Remember those early Republican debates during the last cycle, when so many contenders fanned out across the stage that they looked like misbegotten Rockettes? We could have twice that number in 2016. We could have a crowd scene in “Cats.”

So I’d say to Romney what he said to The New York Times’ Ashley Parker when she asked him early last year about one more campaign:

“Oh, no, no, no. No, no, no, no, no. No, no, no.”