Eric Schmidt (left) with Alan Davidson and an unidentified mime

“It’s been a remarkable experience — and a very exciting and intense time — but I’m ready for a new challenge,” Davidson said in an email to colleagues. “After six and a half years, I’ve decided it’s the right moment for me to leave my current role at the company. Starting later this month, I will be taking a sabbatical to explore other opportunities.”

Davidson’s departure is a bit of a surprise, and a real blow to Google. He was the company’s first full-time lobbyist in Washington and the guy who established its presence in the Beltway. He’s leaving at a time when Google is mired in all sorts of regulatory issues and facing increased scrutiny of its operations. So the company is understandably scrambling to replace him. Sources say it’s hoping to replace Davidson with a former member of Congress in an effort to further bolster its Capitol clout.

Sounds like exactly the sort of lobbyist that company chairman Eric Schmidt described in this October interview with the Washington Post.

“The conclusion that we came to [as far back as when I was at Sun Microsystems] is that there are two kinds of lobbying,” Schmidt said. “And this, I think, is grossly unfair but kind of true. There’s the kind of lobbying where you pay an ex-senator to get the current senator to write a sentence into a bill, and there’s no confusion as to what this is about. You are representing your corporate interest. It’s specific to your company. In Washington, for example, you can pay an ex-person $50,000 to arrange a meeting to get that process, to get those five sentences written in this bill, and so forth and so on.”

Davidson’s email in full, below:

From: Alan Davidson
Date: Mon, Nov 7, 2011 at 4:35 PM
Subject: Time for a new challenge
To: Alan Davidson

In 2005, I joined Google in Washington to build a first-rate Internet
policy group. It’s been a remarkable experience – and a very exciting
and intense time — but I’m ready for a new challenge. After six and
half years, I’ve decided it’s the right moment for me to leave my
current role at the company. Starting later this month, I will be
taking a sabbatical to explore other opportunities.

When I started at Google none of us really knew how the Internet, and
this company, would grow and change. The mobile, cloud, and social
technologies just taking hold then are now full-on revolutions today.
At Google, we’ve grown from one person in shared rental space (me!) to
a large regional team with a flagship office in DC. I am intensely
proud of the team we have built throughout the Americas, and the work
we have done.

When we started the office, I knew that we couldn’t affect the major
policy debates of the day alone. It has only been in partnership with
so many of you that we have been able to make progress on many of the
great issues affecting the Internet. As we seek to fill my role, Pablo
Chavez will continue to be a good point of contact in our ongoing work
together. Thank you.

With best regards,
Alan

This is a photo that’s clearly begging for a caption, so sound off in the comments.

How quickly things changed. By 2007, Davidson had been joined by 11 other lobbyists, among them a former high-ranking Justice Department antitrust lawyer. And now, two years later, Google CEO Eric Schmidt has been named by President Obama to his Council of Advisors on Science and Technology. In that role he’ll work with a group of distinguished academics and executives–a group that, incidentally, includes Craig Mundie, chief research and strategy officer at Microsoft (MSFT)–to help the administration “formulate policy in the many areas where understanding of science, technology, and innovation is key to strengthening our economy and forming policy that works for the American people.”

Schmidt’s appointment isn’t all that surprising. He served as an informal adviser to Obama during his campaign and he’s a smart guy who’s got some strong opinions about network neutrality, next-generation broadband, and intellectual property–issues that figure high on the president’s tech agenda. Still, it’s one more indication–and the biggest one yet–that Google has become firmly part of the Washington establishment.