@Sanigo:
So you actually thinks Ace dying will make everything stop and Whitebeard will retreat like a dog? Ace triggered the war, that much is obvious, but the all-out fight won't stop until one side emerges victorious, which will be the government. Nothing Ace-related will change that, moron.
Just because you don't want to except the fact that the war is based around Ace. Doesn't mean shit. Just understand when Ace is rescued WB wins. When Ace dies WB loses. Get over yourself. Just answer me this since you said the fighting won't stop until a side will emerge victorious what will decide this? WB dying ? Maybe all the admirals and Sengoku getting killed? Does all of the WB crew and the pirate fleet he came with have to be killed or does all the marines have to die? Just tell me what will indicate that some one is victorious in this war to you? If ace war started based on the capture of Ace. WB goal is to rescuse Ace? Good job with the name calling stay classy.
I have to agree with Sanigo on this matter. Even if Ace were to die the War wouldn't have been stopped.
Funnily enough this matter was adressed in the manga itself.

Don't know how much we can trust Garp in that matter but seeing he's an old timer I'd say he'd knows Whitebeard pretty well.
It's not only about Ace anymore, it's about the Worldgovernment daring to challenge Whitebeard so openly.
Announcing to publicly execute one of Whitebeard's crewmember is an insult and the government has to be taught a lesson for such disrespect.
Of course the main motive to participate in the war is and will be saving Ace. But at the same the public annoucement has triggered a reason beyond this IMO.
The only problem I have with that is the you're leaving out the fact that the WB pirates also have reputation to up hold. WB being who is he can not allow the capture or execution of anyone from his crew that shows weakness on his part. So even if they would of killed ace as soon as they captured him they would of still mobilized for revenge purpose and up hold the honor and tradition of the WB crew.
BB also gave Shanks (a yonkou) the scars on his face, even before he had his DF. And Shanks said he was fighting seriously. Don't be fooled by the fact that he got surprised by magellan, he's incredibly strong.
So he scratched shanks in the face sounds like something a chick would do.
The WG + Shichibukai = Yonkou (all four). So I thought from the start that WB is doomed.
It's Mihawk, three Admirals, Sengoku & Garp, other Shichibukai (Mihawk dserves his own mention), VAs and probably the BB crew vs WB, Marco & Jozu, other commanders (one is already gettin' his ass raped), New World captains, and Luffy's gang. You'd have to say the WG are gonna take it, but Oda will throw a twist in here and there.
I'd have to disagree with you luffy's gang is pretty powerful in its on. Also all the shickibukai are not fighting for the WG. Also this could need some verification but I do not believe that BB is using a marine ship if he isn't wouldn't it take him longer to travel to the execution site than luffy and Co. Also we already know that Boa is going to fight along side luffy. Kuma may end up changing sides. There's still a chance of dragon and shanks showing up also.