We have had quite a few Brahmin Prime Ministers, starting with Nehru and then his descendents. Atal Bihari Vajpayee was the last Brahmin minister and looking at the existing political candidates and the trends, there will be some time before we have a Brahmin Prime Minister again.

After the reservation system put a regulating plug into the flow of upper caste young men into the civil services, many of these guys, especially the Brahmins, went into Media, for media is indeed power. Brahmins who were still enamored with politics in an era dominated by caste-based small political parties, went in the service of heads of these small regional parties. Outlook magazine has a feature on the most prominent Brahmin advisors:

BSP MP Satish Chandra Mishra advises UP Chief Minister Mayawati .
BJD MP Pyarimohan Mohapatra advises Orissa CM Naveen Patnaik.
BJP general secretary Arun Jaitley is filling in the tactician's role after the demise of talented Pramod Mahajan, and he wants to become P.M. one day.
CPI(M) politburo member Sitaram Yechury is charting the direction of an atheist party.
Shivanand Tiwari advises Bihar CM Nitish Kumar. Tiwari is a serial advisor. Earlier, he advised Lalloo Yadav. Before that, he advised Nitish. Before that? Lalloo.

Point to remember: Even today, one in 10 M.P. is a Brahmin. The current Lok Sabha has 50 Brahmin MPs, 9.1% of its strength, down from 19.9% in 1984.