Early this year, Politico signaled that it would be expanding its ranks. Months passed, however, without significant movement. The news site recommitted itself to an “aggressive” expansion in late May, upon the announcement that ace reporter Jonathan Martin would be leaving for the New York Times.

Now comes the news that has been simmering in Politico’s offices: Susan Glasser, the editor in chief of Foreign Policy magazine, is making the trip to Rosslyn to captain “new editorial divisions that produce deep, magazine-style journalism and in-the-moment opinion pieces,” according to a Politico memo.

It’s a colossal move. Glasser is a big name in Washington journalism, fresh off of five years spent turning Foreign Policy into a digital force. The magazine had significant print bona fides at the time of its September 2008 purchase by The Washington Post Co., yet its Web presence lagged behind the standards of the time. Upon taking the job, Glasser quickly finished off a redo of foreignpolicy.com that had been in the works — and the magazine’s Web evolution hasn’t slowed since. According to a news release from the Foreign Policy Group, the magazine’s site tallied 4.4 million unique visitors in April, breaking readership records.

“Susan has been instrumental over the years in helping to build Foreign Policy into the thriving, internationally respected media organization it is today,” said David Rothkopf, CEO and editor-at-large of the FP Group. “We’re grateful for her leadership and all of her tireless efforts to expand Foreign Policy’s multi-award-winning coverage in both print and online, and we wish her the best as she moves on to pursue new career challenges.”

Glasser will have a twofold mandate at Politico: One is producing long-form pieces with significant gestation periods. Much of this stuff will land in a new Politico magazine that will come out at least six times per year, according to Politico Executive Editor Jim VandeHei. This magazine will be “stocked with profiles, investigative reporting and provocative analysis.” The other is to generate “of-the-moment” opinion pieces off of the news — kind of a faster-paced version of what Glasser did when she helmed the Outlook section of The Post. The goal is two such pieces per day.

Nor will Glasser have to do all of this alone. According to VandeHei, 12 new hires — a mixture of reporters and editors — will come aboard to assist in building out this new component of Politico. As part of the move, VandeHei & Co. are looking for “several prominent magazine writers to do long-form journalism,” an announcement that is right now prompting a frenzy of resume-updating. Though these folks will report to Glasser, the long form-cum-opinion dimension of Politico won’t be split from the rest of the organization. Says the memo: “Susan’s operation will not be a separate island. She wants and we expect her to be fully integrated within POLITICO.”

The way VandeHei explains it, Glasser’s hire is just part of Politico’s evolution. After the site’s 2007 launch, he says, it managed to “punch through” the noise by spreading its particular form of fast-paced journalism around the Web. But then everyone acquired speed. Breaking news was another way of “punching through,” says VandeHei. But a lot of others break news as well. The new focus, he says, is “to be distinctive — that’s how you punch through.”

Just how distinctive? Anthony Weiner distinctive, says Politico Editor in Chief John F. Harris. That’s a reference to the long piece in the New York Times Magazine on the former congressman who disgraced himself on Twitter and is now running for mayor of New York. Written by Jonathan Van Meter, the piece tore through Weiner’s debacle, his relationship with his wife, Huma Abedin, and riffed on the politician’s future. “That story could and should be in Politico,” says Harris, putting just a touch of altitude under the bar for Glasser.

Though in the past Politico has had editors with the ability to edit long-form stuff — the now-departed Bill Hamilton, currently of the New York Times, comes to mind — this latest move marks a commitment. “We haven’t been previously organized to do that story,” says Harris of the Weiner piece.

That said, the addition of Glasser and a move to a think-ier brand of Politico journalism won’t detract from the site’s speed and voracity for breaking news, says the site’s brass. “This only adds,” says VandeHei.

Politico’s leadership is banking on Glasser’s record of transformation at various entities over her Washington career. Under her direction, Roll Call was the “Politico of the 1990s, creating the next generation of political reporters,” says VandeHei, who worked for her there. Of Glasser’s stint at Outlook, the Politico memo says, “it has rarely been more provocative or essential.” In a stint running The Post’s national desk, Glasser stumbled, alienating staffers to the point that newsroom leadership conducted an internal investigation of her management approach. She was removed from that job in April 2008. Says VandeHei of that episode: “You never force change without alienating some people. John and I felt then as we do now: Susan is a unique talent and supremely gifted editor and thinker.”

And at Foreign Policy? “She made that — next to us — the most successful niche site, at least in our general news space. She was able to command a big, important audience and smart people had to reckon with it,” says VandeHei.

It’s here that a touch of irony enters the picture. Glasser has thrived at Foreign Policy by essentially Politico-icizing Foreign Policy. She upped its metabolism, created blogs and boosted its traffic. The first accomplishment cited by Glasser in her farewell memo to her staff is this:

From its guerrilla launch in January 2009 after just six weeks, the new FP.com last month reached its biggest audience ever, with 4.4 million unique monthly visitors and counting.

She also cites this: “Our annual Top 100 Global Thinkers year-end issue has become one of FP’s marquee features as well as a successful annual event drawing dozens of the thinkers to Washington.” That sounds a lot like something that good ol’ Politico would do.

In other words: Does Glasser align more closely with where Politico has been than where it now intends to go? That’ll be an interesting dynamic, because if awards were given for strong workplace cultures, Politico would receive the Atlas Prize. It exists to crank out fast-twitch journalism on the day’s news. And when the news cycle slows down, it does news analysis pieces that have an uneven track record.

Politico’s bosses clearly have a high opinion of Glasser, because they’re asking the world of her. On the one hand, she’s got to be sufficiently plugged into the news to pilot two quick-opinion pieces per day. She’ll likely inherit Politico’s existing columnists — Rich Lowry of the National Review and MSNBC’s Joe Scarborough — and other opinion pieces that make their way onto Politico.com. On the other hand, she has to plan long-range material — memorable stories that will complete Politico’s journalistic challenge to the New York Timeses and The Washington Posts. Isn’t that enough of a job on its own?

Unclear: Must Glasser create a new culture at Politico, one that competes with the longstanding approach? Or must she co-opt the existing one by adding some modifications here and there? Or is the idea to do both of those things and ride them into a brand-new Politico golden era? Probably. “She operates in multiple gears,” says Harris.