Hey,
@Charcolt Do we know the current strength of Stannis' and Renly's armies compared with our own? If Renly's force is larger than Stannis' and ours combined, I'm not sure getting ourselves involved will be worth the risk. We still have F/Aegon's and Dany's invasions to deal with, not to mention threats from the wildlings and Ironborn. Getting involved in a situation that could potentially resolve itself without intervention would waste resources we might need later.
@Charcolt, is the Vale on our side, regardless, or do we need the betrothal to tie them to us permanently?