Sprint has already got $3.1bn from Softbank in the form of a convertible loan - I think this enables them to do Clearwire irrespective of whether the SB/Sprint deal gets approved - if the deal is blocked then SB will simply be a lender to Sprint rather than a shareholder/owner. Having bid $2.2bn for Clearwire, there is even some scope for Sprint to up the bid in the event of a counterbid (like the one from Dish). The issue, if the SB/Sprint deal is turned down, is how Sprint will fund the rollout of the 2500 spectrum from Clearwire, given that the second installment of cash from SB (4.4bn) would not be forthcoming.