When presidents are on their way out of office, they start talking about their “legacy.” How will history remember them, they wonder? But by then, it’s too late.

We think President Obama should start thinking about his legacy now, at the beginning. We are even willing to offer a little help.

The first thing to keep in mind is that excitement and popularity in your own day don’t add up to appreciation and respect in history. Lincoln was unpopular in his day; Nixon was reelected by a landslide. Good will from fans doesn’t matter to history. Only your actions do.

The first thing you’ll want to do is to avoid becoming known as someone who did terrible things. So, President Obama, for starters, here are four things you do not want to be known as.

1. The President Who Gutted the U.N. Declaration of Human Rights.

Last year, the world marked the 60th anniversary of the 1948 Universal Declaration of Human Rights. That landmark document was able to pull one good out of the crazy death ideologies of the 20th century, by advancing human understanding in opposition to them.

Says the declaration: “Everyone is entitled to all the rights and freedoms set forth in this declaration, without distinction of any kind, such as race, color, sex, language, religion, political or other opinion, national or social origin, property, birth or other status.” Notice the word “birth.”

It went on to add: “Everyone has the right to life, liberty and security of person.” Notice the word “life.”

Mr. President, opponents of that document in your party want to change not just the bits about the right to life, but also references to marriage being for men and women, the importance of the family, the importance of motherhood, and the right to choice in education.

Don’t let them.

Get rid of the right to life, and you’ve given world governments the power to decide on a whim who lives and who dies. They will use it in ways that will horrify the world. They have done so before — and are doing so now.

Get rid of the definition of marriage, and you will open the door to abusive fathers, polygamist oppressors and abuses neither of us can imagine, in which unscrupulous men use “marriage” for selfish purposes.

Get rid of the importance of motherhood, and you’ve lost a core value of humanity — the oldest of the “old things” you praised in your inaugural address. Get rid of the right to choice in education, and you will give the right of thought-control to all governments, from the most benign to the most malevolent and every gradation in between.

2. The President Who Nullified Nuremberg Standards.

Unfortunately, you already became this president. Change that.

By allowing federal money to be spent on embryonic stem-cell experiments, you have essentially turned over a portion of every American’s paycheck to scientists to do fatal experiments on human beings. Many of the “excess embryos” these scientists wanted to kill over the last seven years have been rescued and now are little boys and girls going to school.

Many of them watched your inauguration.

The Nuremberg trial for war crimes established standards of experimentation on human beings that governments have respected ever since, including: “No experiment should be conducted where there is ... reason to believe that death or disabling injury will occur.”

Perhaps you think that these are “only embryos” and that you haven’t really violated the Nuremberg Code. It would be helpful for you to recall that the Nazi scientists thought that, since their patients were “only Jews,” they weren’t violating a code of honor, either.

In the end, only science should determine the humanity of these victims, not our feelings toward them. Embryos are fully human boys and girls whose DNA already has determined their smiles, athletic abilities, likes and dislikes. If you don’t think they’re human, meet the many rescued “embryos” George Bush brought to the White House once they had grown a little. (History will praise him for this.)

3. The President Who Dehumanized the Handicapped.

It was already unfortunate that you called supporting Terri Schiavo your greatest mistake in your Senate term. The handicapped, even the severely handicapped, are in one way the truest test of a culture’s greatness. How we treat them shows the measure of our compassion and hope for the future, because it shows our respect for the vulnerable.

The ugliest moment of the last campaign was when some members of your own party suggested that Sarah Palin should have aborted her child when she found out he had Down syndrome. You may want to right that wrong now that you’re in office.

Perhaps you can help raise awareness of the beauty of Down syndrome children. Sarah Palin has good ideas in this regard. Call her.

4. The President Who Sided With Money on Abortion.

When you step outside of our time and look at 2009 from a position of history, it’s clear to see that the pro-abortion (or, if you prefer, “pro-choice”) position is a big loser. As even the Supreme Court has recognized, women who choose to abort their children suffer for years to come — and the children who were chosen to be aborted, of course, are killed.

Right now, ideologues in the media keep silence about abortion. They ignore Post-Abortion Syndrome. They ignore the footage of actual abortions, where babies’ torn body parts are assembled on tables. They ignore the fact that big money is being made by an industry that kills human beings for profit. That won’t last.

When people look back on your presidency, do you want to be known as a man who, faced with this horror, sided with the guys making money off it? Mark these words, write them down and save them: If you keep to your radical pro-abortion position, within a few decades, people who cheered you this January will pretend they didn’t vote for you, out of shame.

Change is good, and hope is a virtue. But the good feelings the nation has about hope and change will only last until the change is actually made. At that point, only the content of the change matters: Did it make the world better or worse?

All the good feelings in the world today won’t add up to good feelings in the history books. That will only come if you do good — and avoid evil.