The campaign trail seemed a universe away from Southern Methodist University's John Tower Center last week, where Andy Card and Mack McLarty held forth for more than an hour about the realities of running a government.

They know something about that. Card was George W. Bush's first White House chief of staff; McLarty held that post under Bill Clinton. Those grueling tenures showed them what it's like to manage a president's day, hire and manage Type-A staffers, keep an agenda rolling and deal with Capitol Hill.

The longer they talked the other night, the more being president sounded as disconnected from what John McCain and Barack Obama are doing on the stump these days as pitcher-and-catcher camps are from the realities of a marathon baseball season.

Here are some pointers that John McCain and Barack Obama might want to keep in mind:

FORGET ABOUT THE LOVE

Candidates, as Card aptly put it, have to be "love magnets." Their primary job right now is to get voters to swoon over them. Hence, the baby kissing, pancake flipping and crowd pleasing.

For the winner, the dating ritual ends when he becomes president. His job shifts radically, starting during the transition period between election and inauguration. Card offered the best description I've heard of the ultimate calling: "A president must find the courage to be lonely."

Obama especially should consider this. He has been campaigning for a year before worshipful supporters.

If he wins, he will have to disappoint some of that throng if he's going to be a great leader. A president, after all, has to make calls in the national interest, not just in the interest of devoted supporters.

THERE IS NO SCRIPT

Both chiefs of staff talked about meeting actors from "The West Wing," the popular television drama. Hollywood's White House, of course, was fictional and followed a script; Washington's reality show has none.

In other words, the smarty-pants in the McCain and Obama campaigns had better get ready. Some parts of running a White House are common sense, like meeting with foreign leaders. But this leaves out what McLarty calls UFOs: the unforeseen occurrences that fly in all the time.

How presidents respond to them will shape their legacies more than what they say at a campaign rally in Scranton. Bush rallied America after Sept. 11, but he also personalized that terrible day in a way that led to bad calls. Notably, his devotion to protecting the country led him to support torturing suspected terrorists.

THE HIGHS WILL BE HIGHS

We know presidencies have low moments — does Monica Lewinsky ring a bell? — but they also experience highs that remind presidents why they do what they do.

Card remembered Sept. 14, 2001, when Bush touched a nation's grief-sick soul with his National Cathedral address and several hours later grabbed a bullhorn on Wall Street and let the terrorists know this country wouldn't back down.

McLarty recalled a woman stopping Clinton on a rope line and thanking him for reforming welfare. When she was on assistance, she told him, she couldn't tell her child's friends what she did. Now that she had a job, she could say the words with pride.

Those are the moments when governing and campaigning come together. If you make the tough calls, like going against your party on welfare, people will appreciate you. But you can't become Abraham Lincoln if you only want to be loved.

William McKenzie is an editorial columnist for the Dallas Morning News.