Sneak Peek: "What Do I Need to Know, Johnny?"

Terry Nelson was essentially pushed out, Rick Davis was brought in on top, and John Weaver quit -- that's the bottom line from Tuesday's major shakeup of the McCain campaign, per ABC News' John Berman.

McCain, who was clearly not happy with his campaign's profligate spending, orchestrated the shake-up which has been in the works for a while.

The Arizona senator made clear his displeasure and intention to install Davis -- who managed his 2000 presidential bid -- in the campaign's top job. And depending on whom you believe, Nelson either resigned, or was fired, or was about to be fired.

And when it was clear Davis was being brought in, Weaver quit. There is some bad blood there going back years.

  "While McCain didn't directly whack Weaver," writes Berman, "it was clear to pretty much everyone (and McCain had to know) that he wouldn't stay if Davis was brought back in."

  McCain wasn't as close to Bush veteran Terry Nelson.

He is being blamed, according to Berman, for trying to run McCain's '08 bid like a Bush campaign: "spending a gazillion dollars, with a huge staff, and tons of endorsements."

While getting rid of campaign manager Nelson was more of a business decision for McCain, saying goodbye to chief strategist Weaver was painful for the Arizona senator.

"I'm the one guy who can tell John 'no,'" Weaver told the Washington Post's Dana Milbank in a memorable 2000 profile.

While Davis may not be as well known as Weaver for throwing things, he is no stranger to "stirring up a few hornet's nests."

Davis is the one who urged McCain in 2000 to give a speech in Virginia Beach assailing Pat Robertson and Jerry Falwell as "agents of intolerance."

"'For us it's no net loss,'" Davis told the Washington Post's Tom Edsall at the time, "because Robertson will continue to try to defeat McCain no matter what."

To the chagrin of those who love political memorabilia, Tuesday's shake-up means that there will be no 2008 "little older, little grayer" version of the February 2000 New York Times front-page photo of McCain, Weaver, and Davis in the "Tonight Show's" green room.

As for Wednesday, McCain tends to his Senate duties in Washington, DC, one day after delivering an Iraq speech in which he stuck with President Bush on the way forward in Iraq. LINK

Rudy Giuliani, who rolled out his foreign-policy team and reacted to Vitter on Tuesday, has no public schedule on Wednesday but he will find himself in the crosshairs of the nation's firefighters union. LINK

Per ABC News' Rick Klein, "The nation's largest firefighters union is set to launch a video on Wednesday that seeks to tarnish former mayor Rudolph Giuliani's reputation as a strong leader before and after the Sept. 11, 2001 terrorist attacks." LINK

The Giuliani campaign is pushing back with former FDNY Commissioner Howard Safir saying: ""Firefighters across the country have no greater friend than Rudy Giuliani."

On Capitol Hill, the Senate Judiciary Committee hears from former White House political Director Sara Taylor at 10:00 am ET, and the House Judiciary Committee hears from Amb. Joe Wilson at 12:00 pm ET.

As for the Democratic presidential candidates, Bill Richardson does the Field of Dreams thing on Wednesday. During his Iowa swing, he makes appearances in Dyersville, Manchester, Independence, Waterloo, and Cedar Rapids.

John Edwards holds a 3:00 pm ET town hall meeting at Sheet Metal Workers Local 88 in Las Vegas followed by a media availability.

Hillary Clinton joins Harry Johns, Alzheimer's Association President and CEO, at 9:30 am ET in welcoming the formation of a bipartisan study group to examine the response to Alzheimer's disease in Russell 428-A.

Barack Obama spends his day in Washington, D.C.

The American Federation of Teachers hears from Chris Dodd and Dennis Kucinich on Wednesday. The AFT heard from Clinton, Edwards, Obama, and Richardson in May.

As for the other Republican presidential candidates, Sam Brownback speaks at the Greater Des Moines Partnership at 12:30 pm ET.

Mike Huckabee is in Iowa meeting with supporters in Sioux City at 11:00 am ET and Le Mars at 12:00 pm ET. He then hosts a conference call with bloggers at 3:00 pm ET and holds a media availability at 3:30 pm ET. Huckabee ends the day with a meeting with supporters at 5:30 pm ET in Sioux Center and a house party at 7:30 pm ET in Granville.

Tommy Thompson continues to crisscross Iowa appearing in Allison, Hampton, Mason City, New Hampton, Waterloo and Grundy Center.

Newt Gingrich attends a reception with the Virginia Republican Party in Norfolk at 6:00 pm ET.

As for President Bush, he and first lady Laura Bush participate in an 8:05 am ET ribbon-cutting ceremony for the James Brady Press Briefing Room at 8:05 am ET.

President Bush also makes budget remarks at 1:05 pm ET.

POLITICAL STORIES ON ABCNEWS.COM:

ABC News' Rick Klein: "Firefighters Burn Giuliani's 9/11 Image" LINK

ABC News' Jake Tapper "Sen. Vitter Apologies for his link to DC Madam" LINK

USA Today's Susan Page "Bush Approval Rating a New Low" LINK

ABC News' Z. Byron Wolf "McCain Denies Staff Departure Part of Campaign Shake up" POLITICAL VIDEO ON ABCNEWS.COM:

Giuliani's Vitter Disappointment LINK

McCain Stands By Iraq Strategy LINK

Clinton's Plan to End the War LINK