Caste in india is complex, complicated and difficult to comment on in a cursory post such as this. However, as a simple truism what can be said is this: the middle castes are often in a zero sum game against each other. The upper castes and the Dalits are not — at least not among themselves. The upper castes are by definition of the pyramid few in number. Members of one upper caste group are unlikely to look at another upper caste group as a direct threat to their prosperity or security. They may not marry each other or at times even drink water from each others’ house; but for purposes of politics and fight for resources, they don’t rival each other. Similarly, Dalits of one sub-sect many times don’t marry into another. But as a group, their agitational politics is largely not in conflict amongst the sub-groups.
The difference is quite dramatic when one considers the middle castes. In large parts of the country, they view each other as a direct threat to resource allocation for their group. For example, a political party in Tamil Nadu is never going to get Mukkulathor and Nadars to both overwhelmingly vote for it. And, it wouldn’t want to have a person from one of those large caste groups to dominate the party either — which partly explains M Karunanidhi, MG Ramachandran and J Jayalalitha as party chiefs, all belonging to obscure and tiny caste groups — to avoid the party be seen as associated with the dominant OBC caste to make the other OBCs nervous.
That basic rationale of competing groups appears to hold in UP and Bihar as well if the evidence of their polity is considered. Yadav’s, one of the numerically dominant OBCs in both states, have a party of their own — SP & RJD — albeit in a social coalition with Muslims and some others. Their rival OBC caste, the Kurmis and Lodhs, for instance, seem to have a rival camp: Nitish Kumar and Kalyan Singh being examples. These OBC groups from their core caste base and then go about building a social coalition outwards — preferably with numerically weaker other OBCs or Muslims or Upper Castes. And yes, given these middle castes are the direct oppressors of Dalits in most places, a coalition that includes the Dalits becomes extremely difficult for an OBC credential claimant.
Thus, unless someone actually belongs to a numerically strong OBC locally it makes no practical sense to claim that in campaigning. Either overtly or covertly. In other words, the entire spiel about Mr Modi’s OBC appeal in the Gangetic Plains is nonsense. Actually belonging to an OBC in such a scenario may be a worse thing electorally than belonging to an upper caste. After all, OBCs don’t compete with upper castes for jobs and quotas. They compete with other OBCs.