Because fish have to swim and birds have to fly, those of us lucky enough to spend our time on politics somehow feel we have to predict the winners of national elections.

This is the 12th presidential campaign that I have either worked in or covered. What follows is how I try to forecast the winner when a U.S. president is running for re-election.

First, I want to know as Election Day approaches how voters feel about conditions in the country. My favorite question is, “Do you think things are generally headed in the right direction, or do you feel things are off on the wrong track?” Our survey finds that 40 percent of voters say things are headed “in the right direction,” while 48 percent answer things are “off on the wrong track.” Not exactly whistling a happy tune, but not in pessimism’s dark night, either.

Second question we need answered: “Do you approve or disapprove of the job (name of the incumbent) is doing as president?” Here, our voters are evenly divided, with 49 percent approving the job the president is doing and 48 percent disapproving.

Then, “How would you feel if (incumbent president) were re-elected in November — optimistic and confident he would do a good job, satisfied and hopeful that he would do a good job, uncertain and wondering whether he would do a good job or pessimistic and worried that he would do a bad job?”

Fifty-one percent of the voters interviewed would feel positive (optimistic and confident or satisfied and hopeful) if the president were to win a second term, while 48 percent would feel negative (uncertain and wondering or pessimistic and worried). Again, almost an equally divided electorate.

So, given these numbers, who will win? We already know, because these were the answers given to the Wall Street Journal-NBC News poll in late October of 2004, just before President George W. Bush captured 50.7 percent of the national vote and 286 electoral votes (270 needed to win), with Ohio’s electoral votes providing the margin of victory over Sen. John F. Kerry.

The two highly regarded professionals, Democratic pollster Peter D. Hart and Republican pollster Bill McInturff, who conduct the Wall Street Journal-NBC News poll asked those same questions this October. Here are the big surprises:

In 2004, 40 percent of the voters saw things “generally headed in the right direction,” while in October 2012, 41 percent saw the U.S. headed in “right direction.” Then, 49 percent approved of the job the president was doing, while 48 percent disapproved. And at the same point in 2012? You guessed it: 49 percent approved of the job the president was doing, and 48 percent did not. Fifty percent felt positive — either optimistic and confident or satisfied and hopeful — about a President Obama victory.

There you have it. My best guess is that the 2012 election results will end up looking an awful lot like the nail-biter presidential contest of 2004, when if John Kerry had just won Ohio and its electoral votes, he would have won the White House.

Credit for President Bush’s 2004 Ohio victory has been given to his campaign’s and the Republicans’ superb organizational operation in identifying the Bush supporters and then making sure they voted. This year, most observers give the organizational edge to President Obama’s side.

How many times have we read or heard about the “vaunted Obama ground game?” “Vaunted” — which comes from the Latin vantare, to boast — is one of those words that conveys skepticism or even disbelief, as in, the “home team’s vaunted defense was shredded.”

I am not about to bet the rent money on the 2012 election. But I will make one iron-clad prediction. The losing party, regardless of whether it’s the Dems or the GOP, will blame its defeat squarely and entirely on its losing nominee.

Mitt Romney would be pilloried for having lacked the common touch and for being inconsistent and contradictory in his beliefs. Barack Obama would forever be blamed for a visionless campaign and for his abysmal performance in the first debate, when he allowed Romney to recast himself from immigrant-hunting, saber-rattling, cut-taxes-on-the-wealthiest Mitt into reasonable-Massachusetts-moderate Mitt.

You can take that to the bank.

To find out more about Mark Shields and read his past columns, visit the Creators Syndicate web page at www.creators.com.