Maybe a year ago we all would have been shocked by the John Edwards affair. A mistress! A baby! A strange, sexually-charged incident in the men’s room!

Now it just feels like one of those chapters they add to a textbook so college students can’t buy the used edition at half price.

Doesn’t it seem like we’ve already learned everything possible about politicians’ peccadilloes (emphasis on their peccas) for more than a year? Thanks to Eliot Spitzer, Governor Paterson, Vito Fossella, Governor McGreevey — back for second helpings of humiliation — and, of course, restless leg Larry Craig, it’s like we’ve taken Advanced Placement Sleaze and aced it. We officially are adults now, just like French people, but without the delicious pastries and nude First Lady.

Just in case there’s a pop quiz, however, here’s a cheat sheet about cheats between the sheets:

THE LESSONS WE’VE LEARNED FROM A YEAR OF STUDYING GUYS AND DOLLS (AND GUYS, AND SOMETIMES BABIES, AND AT LEAST ONE THREE-YEAR-OLD) IN POLITICS

1. If it’s a choice between believing a politician and the National Enquirer, go with the one that also features celebrity cellulite shockers and dirt on Rosie O’Donnell.
2. When a politician says he did not have sex with “Person A,” it’s because he doesn’t yet realize that there are photos. And a wiretap. And a guy from the National Enquirer.
3. And sometimes a receipt.
4. Also “Person A” is blabbing to half the world and keeps cashing campaign checks.
5. You don’t have to be a young woman to be a powerful man’s mistress.
6. Sometimes, you don’t even have to be a woman.
7. Men in power choose their paramours by proximity, peroxide, or payment method. Or by whoever’s in the next stall.
8. If a politician isn’t getting fat, there may be a reason.
9. It’s hard to hear any politician talk about moral values without wondering, “Is that the same shirt he was wearing yesterday?”
10. When a politician says he has been forgiven by his family and God, ask yourself, “How would he know if God really forgave him?” Then ask yourself that about the people standing next to him on the podium with their teeth clenched.
11. If there were a law that would allow us to remove the offending husband from office and swap in his wife or grown daughter, we’d all relax.
12. We don’t like a guy more if he likes his doll less.

LESSONS OUR LEADERS HAVE LEARNED THE HARD WAY (SO TO SPEAK)

1. You take your socks off. You put your condom on.
2. If you’re going to have sex with a woman of childbearing age, she just may.
3. If you’re going to have sex with a man, he won’t. Doesn’t mean the public will be a whole lot more understanding.
4. Just because you’re blind doesn’t mean other people don’t see you.
5. Avoid hotels between 2 a.m. and 7 a.m.
6. Once you get a $400 haircut, no one really trusts you again.
7. People will remember whatever you said about “that woman” a lot more vividly than they will ever remember anything about your clean coal bill.
8. Two heads are better than one. Two families, no.
9. When making a Web video to advance your presidential aspirations, it is prudent to edit out the giggles.
10. If you’re going to admit your indiscretions, admit them all at once, so there’s less footage for YouTube.
11. If you’re going to proudly declare yourself a gay American, do it before you’re caught with a member of your same sex and no pants.
12. Pay cash for everything you shouldn’t be paying for at all.
13. If you want to keep your lovechild a secret, don’t try to get out of a ticket by telling the cops that’s who you’re off to see.
14. When you say, “If you want to beat me up, feel free” — they will.
15. If you’re going to admit to an affair, do it on the day the Olympics start.
16. By the time you are hiding out in a men’s room, all bets are off.
17. By the time you are hiding out in an airport men’s room, all belts are off, too.

lskenazy@yahoo.com