As The Washington Post’s Chris Cillizza notes, the news already seemed like old news when former NYC Mayor Rudy Giuliani announced that he was leaving the Presidential race.

It’s a testament to how fast-moving this election cycle has become that even before former New York City Mayor Rudy Giuliani is scheduled to end his campaign and endorse Sen. John McCain (R) later today, the development already feels like old news.

But it would be a mistake to gloss over the Giuliani endorsement without weighing the impact it will have on the race. And since we don’t like to make mistakes here at The Fix, we’ve spent the last few hours talking to party operatives in an attempt to understand what Giuliani’s support for McCain means and what it doesn’t.

As with any high-profile endorsement, Giuliani’s decision to back McCain works on both a symbolic and a practical level.

The symbolic is more important in the larger fight for the nomination, so let’s start there.

Although it’s easy to forget given the utter collapse of his campaign over the past month, Giuliani spent the majority of the Republican presidential race as its leader — thanks to sky-high name recognition and favorability ratings due at least in part to his handling of the aftermath of the terrorist attacks of Sept. 11, 2001.

In the months and years leading up to his presidential bid, Giuliani was among the most coveted Republican surrogates on the campaign trail. Senate, gubernatorial and House candidates all clamored for an event with Hizzoner, knowing that not only would it bring in scads of campaign cash but also that it would identify them with Giuliani’s sterling brand.

That brand has been tarnished somewhat by Giuliani’s lackluster presidential bid, but for the average Republican he remains an American hero and a symbol of what is good about the Republican Party.

Thus, by scoring Giuliani’s endorsement, McCain can bask in the goodwill that most GOP faithful still hold to Giuliani while also using Hizzoner’s backing to suggest that the party is starting to rally behind him.

In his concession speech last night, in the aftermath of losing the Florida Republican primary, Giuliani reflected upon his campaign as one of ideas and not personal attacks.