After producing a stunning result in the Delhi state election in December and then forming a government, the Aam Aadmi Party faces the difficult task of governing, said Lloyd and Susanne Rudolph, political scientists who have studied India for more than five decades.

But the Aam Aadmi party does not have an adequately institutionalised response to various issues, said the two Americans, now in their early eighties, who were awarded the Padma Bhushan in the literature and education category.

Yet it would be a pity if AAP does not live up to people's expectations, they said, because India's biggest challenge is that its political system is not functioning well and is unable to make parties deliver badly needed public goods, such as education.

Besides the Rudolphs, Anisuzzaman from Bangaladesh was the other foreigner awarded a Padma Bhushan, also in the same category. The Rudolphs have written eight books about Indian regionalism, identity politics, the bureaucracy and state formation, among other things.

"It's wonderful to have spent 50 years researching and writing about India, living there with our family," said Lloyd Rudolph over the phone from Berkeley, in the US. "To have that kind of recognition is very warming to the heart." Although his wife's health is a concern, he said they hoped to be in India in March to collect the award.

After retiring from the University of Chicago in 2002, following a hugely productive research career in which they also mentored dozens of students, they continued to do research on India, and have two more books in the pipeline. "We see huge problems," said Lloyd Rudolph. "But we are very committed to India."

The Rudolphs, whose huge body of work on India includes path-breaking research on caste, said that this traditional institution, had, contrary to standard theories of modernisation, actually facilitated democratic participation. But caste has now becoming self-serving.

"Today, people are in it only for the benefits and the resources they can get a hold of because of their caste," said Susanne Rudolph. "It has become more infected with muscle power and violence."

In what is arguably their most influential book, 'The Modernity of Tradition', the Rudolphs had argued in 1967 that caste in India could not be simplistically wished away as a traditional institution.

Going against the grain of modernisation theory, which argued that caste would impede India's march towards democracy, they showed how the traditional institution actually became a vehicle through which India's masses demanded and won political rights and social justice after Independence, when all citizens got the right to vote

"The question of how developed a country needs to be in order to have democracy is one that has produced the most scholarship in comparative politics," said Mona Mehta, a political scientist at IIT Gandhinagar, who was among the Rudolphs' last graduate students. "You can't overemphasise the importance of this book in challenging modernisation theory, the dominant paradigm of that time."

In addition to studying India and its politics, the Rudolphs played a tremendous role in influencing debates about methodology that had gripped US political science departments in the '80s and '90s, said Mehta. They were central figures in asserting the importance of detailed qualitative and ethnographic research at a time when political science departments in the US were being swept by the move towards quantitative methods, she said.

Furthermore, while acknowledging the importance of globalisation in influencing local issues, they continued to emphasise the importance of understanding local structures and politics. "These were the people who told us about the importance of situated knowledge," said Mehta. "They stood for extremely rich, qualitative research on South Asia."

Ananya Vajpeyi, a historian and author of the award-winning book, 'Righteous Republic', was among the numerous young scholars whom the Rudolphs nurtured. She was a student at the University of Chicago when they headed the institution's highly prestigious Committee On Southern Asian Studies and has known them since 1996.

"They really helped when I was writing my book," she said. "I needed a lot of guidance with many of the arguments I was trying to make. They were very helpful when I had to think through Gandhi."

The Rudolphs have written extensively about Gandhi, including the books 'Postmodern Gandhi and Other Essays: Gandhi in the World and at Home' and 'Gandhi: The Traditional Roots of Charisma', a slim volume that Mehta described as "a gem of a book."

Of their two books in the works, one will be published in a few months. It contains three parts -- the first is a diary of their overland trip in 1956, when they drove to India via Europe, Iran and Afghanistan, and spent six months each in Jaipur and Madras, while the second chapter is an overview of 50 years of their research --  their main arguments and findings.

The final chapter is an updated version of a powerful speech titled 'The Imperialism of Categories' that Susanne Rudolph delivered in 2005 when she was the president of the American Political Science Association. "She had argued how you mustn't take categories of analysis for granted," said Llyod Rudoloph. "Instead of taking a cookie-cutter approach, a researcher should let questions arise from the context and the field."

The other book, which Susanne Rudolph is still writing, is based on the letters she wrote to her family and friends during the couple's trips to India over the years. "Through those letters one gets a view of post-colonial Indian history," said historian Vajpeyi.

The Rudolphs were also often invited to Washington DC, where they briefed departing ambassadors to India and policymakers, said Mona Mehta, of IIT Gandhinagar. "They weren't just theoretical scholars," she said. "They kept their pulse on 'real' politics."

In India, too, they immersed themselves in the political scene. Over the years, they had met Nehru, Krishna Menon, Khushwant Singh and Romila Thapar, among many others, said Vajpeyi.