The departure of President Bush's close adviser and longtime speechwriter Michael Gerson ends an era in which an evangelical Christian had unprecedented access and influnce in shaping American foreign and domestic policy. Thanks to Gerson's humility, he never came close to receiving the attention from journalists of the likes of Karen Hughes and Karl Rove, but few were as influential. Fortunately, a few journalists were smart enough to spot the influence of Gerson, particularly Carl Canon in this National Journal cover story, which received a Aldo Beckman Award for repeated excellent White House reporting, and Jeffrey Goldberg in a New Yorker profile that received a high level of attention. Appropriately, his exit is receiving attention from Washington's heavyweights:

Here's The Washington Post's Peter Baker:

Michael J. Gerson, one of President Bush's most trusted advisers and the author of nearly all of his most famous public words over the past seven years, plans to step down in the next couple of weeks in a decision that colleagues believe will leave a hole in the White House at a critical period.

Gerson said in an interview that he has been talking with Bush for many months about leaving for writing and other opportunities but waited until the White House political situation stabilized somewhat. "It seemed like a good time," he said. "Things are back on track a little. Some of the things I care about are on a good trajectory."

Since first joining the presidential campaign as chief speechwriter in 1999, Gerson has evolved into one of the most central figures in Bush's inner circle, often considered among the three or four aides closest to the president. Beyond shaping the language of the Bush presidency, Gerson helped set its broader direction.

The WaPo article was a bit more thorough than the New York Times piece, but that's to be expected. I did have one small beef with the Baker piece, though, in his reference to Gerson's sharing Bush's "conservative Christian faith."

Gerson stood out in a White House known for swagger. A somewhat slight, pale, bespectacled and soft-spoken Midwesterner, he nonetheless forged a strong bond with the outgoing, backslapping Texan president, in part through their shared conservative Christian faith. He found a way to channel Bush's thoughts, colleagues said, transforming a sometimes inarticulate president into an occasionally memorable speaker.

I won't contest Bush's conservatism or Christian faith, nor will I contest either for Gerson. But it's just not that simple, as Cannon's profile clearly demonstrates:

Gerson, in what amounted to a self-directed continuing education, had been immersing himself in Catholic social thought, to try to understand the intellectual underpinnings of these issues. (He currently attends the Falls Church, an evangelical Episcopal church in suburban Virginia that was organized in 1734; George Washington served there as a warden.) Gerson had also been studying how Catholic Charities and Lutheran Social Services delivered services to those in need. And Bush -- in part because of Colson's work in Texas's prisons -- had become a convert to the idea that government could work in concert with faith-based programs.

"Catholics have long believed that the state has a role to play in alleviating poverty, but that this is not necessarily a role it plays directly," says Catholic scholar Luis Lugo, director of the Pew Forum on Religion and Public Life. "What has happened in the U.S. is that Protestants have embraced this -- first with school vouchers, and later with prison outreach, poverty, and other issues. It's a growing alliance between Protestants and Catholics to help the less fortunate, and Mike Gerson is at the intersection of these two traditions coming together."

Does description of Gerson's faith dovetail with what we know of Bush's faith and politics? That's a difficult question because much of Bush's personal faith and its connection to his politics is relatively shrouded by political necessity. Perhaps we will learn more once Bush has left office, but until then, the comparison cannot be made.

It's clear that Gerson stood out in the White House. It's not so clear that he and Bush necessarily saw eye-to-eye on everything Christian and conservative. I believe it would be more accurate to say that Gerson's conservative Christianity influenced Bush just as Karl Rove's cutthroat politics influenced him.

To wrap up, I'd like to say that without Gerson, one cannot imagine the course of the Bush presidency. Gerson turned Bush into one of the most articulate presidents of all time at various points in the last five-plus years.

Where would Bush be without Gerson? I point you to the White House transcript of a press conference held Wednesday:

Q: Is the tide turning in Iraq?

THE PRESIDENT: I think -- tide turning -- see, as I remember -- I was raised in the desert, but tides kind of -- it's easy to see a tide turn -- did I say those words?

President Bush is already missing Mike Gerson.