User blog comment:JustSomeDude.../Law's Plan & The Shichibukai/@comment-4800978-20130204235535

I feel it goes back to the end of Part 1, where the reason he doesn't enter the New World is because he wants to "steal the proper throne". This implies it isn't exactly the Pirate King like Luffy intends, so I've been going with the "use the World Powers against each other" idea since seeing his blackmail of Don.

He's already used his position as a means to enter Punk Hazard and manipulate Caesar in their "alliance" (I know the Government isn't involved, but having a Shichibukai on your team is a pretty good deal what with the political freedom and all, so Caesar could hardly of refused). Forcing Don to resign apparently is enough to get the admiral(s) directly involved - so add that to Kaido and you've got a perfect situation where Don is forced to cooperate with Law's plan in order to survive (maybe Law wants to increase that 30% margin) - and that's where I see a betrayal emerging.

Law is playing a dangerous game, and if we don't know his entire plan yet it just means Oda doesn't want us to know (like Luffy's answer to which Yonko they'd take down). I'm happy to just wait and see.