A few weeks ago in Bikaner, a remote district in India's western desert state of Rajasthan, a group of four young men having lunch at the roadside Karan Restaurant said they were ready for change.

Under a Congress party chief minister, the state had brought in a new program to give residents free medicine. The young men liked the program but said they were going to vote in the national election for Narendra Modi and his Bharatiya Janata Party because they wanted a future filled with jobs and economic growth—not more government...