The left fought for social issues and won in the western democracies.
The social issues of left are equality for women (feminism, equal work for equal pay, gender issues, etc.), homosexuals (LGBTQ community) and all races (fight against racism).
In the process of fighting these social issues, the left won political power. More importantly they won the culture war. They could develop dedicated political constituencies which voted for them for fifty years.
In the fight the right was labelled as sexist, homophobic and racist. They lost credibility in society and were proven to be a backward philosophy.
In India the right should integrate these social issues which will strengthen nationalism.