Dear Karl,

It was always enjoyable working with you at the White House in the first years of President Bush’s administration when I was at the Council of Economic Advisers. Although my duties as the Council’s chief of staff didn’t put us in daily contact, our paths intersected often enough for me to see first-hand how much you contributed.

Now that you’ve announced your resignation, some headlines continue to portray you as “Bush’s brain,” a Machiavelli who schemes behind the scenes to manipulate the White House policymaking apparatus. This is inaccurate and unfair to you and to Mr. Bush.

The president has a brain of his own, one whose power exceeds that of most of his staff. The president’s self-deprecating style — he told reporters last week that he could not speak French when visiting with President Sarkozy, and that he could barely speak English — purposely masks his intellectual power.

The press portrays you as all-powerful, dominating the White House policy-making apparatus to the exclusion of other staffers. That is hyperbole, meant to diminish the president. Since I’m not into “kiss and tell,” I won’t mention staffers who aligned themselves for and against you in some policy debates. Suffice it to say that, like all staffers, you win some internal battles and lose others.

Few know about your habitual good humor and frequent forays into practical jokes. I was sitting next to you in the White House Mess when you asked, tongue-in-cheek, to charge your lunch to the account of the chief of staff, Andy Card. You almost got a free lunch.

Although the corridors of power sometimes wear people down, you keep up morale. You make a fuss over colleagues’ birthdays. On Fridays, you treat your staff — and anyone else who happens to come your way — to ice cream. You provide your assistant with delicious snacks that she keeps on her desk and doesn’t mind sharing.

Your genius is that you figured out what would appeal to voters and what would make them vote Republican. You understand that people want to have more control over their lives and their resources, so you helped move forward policy initiatives that accomplished those goals. Attentive to the mundane problems of electoral politics, you devised ways to get people to the polls.

Some of the administration’s policy initiatives — people say they’re yours, but we both know that they were really the president’s — were passed by Congress, such as tax cuts, higher standards for education in the No Child Left Behind law, Medicare Advantage, and broader health savings accounts. All these give people more money, both through economic growth and through lower taxes, and more choice over how to spend it.

Other ideas didn’t make it into law, and you’ve been blamed for encouraging the president to overreach. These ideas include individual control over part of social security accounts, tax deductions for individual health insurance premiums purchased outside the workplace, and immigration reform.

But to say you endorsed overreaching is to misunderstand the fundamental purpose of the presidency, which is to tackle the toughest issues facing America. Any president can successfully rename post offices and federal buildings — but will that change the course of the country? On the other hand, fixing health insurance, or our immigration mess, will make a difference to millions of Americans, now and in the future.

Your critics and adversaries use many derogatory words to describe you. Senator Obama, one of your more polite critics, earlier this week said that you are “an architect of a political strategy that left the country more divided, the special interests more powerful, and the American people more shut out from their government than in any time in memory.”

Your passion is history, and history eventually will reveal whether or not Mr. Obama is right. Will the Bush policies persuade more Americans to vote Republican, or drive them away? Giving people higher incomes and more choices makes them more independent of government, and such independence is desirable. The most inefficient services in our country are run by the government. Just look at the lines at the states’ motor vehicle agencies or the poorly-run inner-city schools.

This is a good time for you to leave the White House because major new domestic policy initiatives are unlikely to come out of this administration in its remaining 17 months. Congress appears intent not only on defeating new Bush proposals but also on conducting investigations into the implementation of previous ones.

You will undoubtedly continue to be a player in the political arena. The 2008 Republican candidates, both presidential and congressional, will be striving for the most politically effective policy platforms and will seek your counsel as a private citizen. With the right advice, Republicans just might take back Congress, contrary to the predictions of many influential pollsters. Although no longer in the White House, you can still chalk up substantial accomplishments in time for the next election. Your phone will be ringing off the hook.

Best wishes,

Diana

Ms. Furchtgott-Roth, former chief of staff at the Council of Economic Advisers and chief economist at the U.S. Department of Labor, is a senior fellow at the Hudson Institute.