Photo

CHENNAI, India — It will take him 12 to 15 hours on a bus, but S. Dorai, a 38-year-old cabdriver in the capital of Tamil Nadu, said he was determined to travel to his native Kanyakumari, at the southernmost tip of India, to cast his vote on Thursday.

India Votes News and analysis on the world’s largest election.

In previous parliamentary elections, he had supported either one of the two regional parties that have dominated this southern state’s politics since 1967, the Dravida Munnetra Kazhagam and the All India Anna Dravida Munnetra Kazhagam.

But Mr. Dorai, who called both ethnic Dravidian parties “thieves,” said this time he would vote for Narendra Modi of the Bharatiya Janata Party, who is also the chief minister of Gujarat. “Mr. Modi has done good work in Gujarat,” he said. “He will do good work in Delhi also.”

Voters like Mr. Dorai are giving the B.J.P. hope that a combination of a growing urban population, disaffection with leaders in the state and in New Delhi, and Mr. Modi’s charisma will help the opposition party make some headway in a state that it has found impossible to crack in the past.

In 2009, during the last national elections, the B.J.P. won less than 3 percent of the vote, compared with the Congress party’s 15 percent. But analysts now expect that a B.J.P. alliance could pick up four to six seats out of the 39 available. The party did not win any seats in 2009.

GRAPHIC Regional Influencers in India’s Elections

The path to prime minister will depend on a familiar group of secondary politicians.

“The support for Mr. Modi is a largely urban phenomenon,” said Sampath Kumar, a former journalist with the BBC and professor at the Asian College of Journalism. “In the rural areas, the Dravidian parties still remain strong. But Tamil Nadu is a rapidly urbanizing state, and that bodes well for him.”

The B.J.P. has long had a tiny base of supporters in the state’s Brahmin community, Mr. Kumar said, which makes up 3 percent of the population of Tamil Nadu. The Brahmins, though still economically and culturally influential in the state, have been politically inconsequential since the late 1960s, when the Dravida Munnetra Kazhagam, a party born of the Dravidian movement that mobilized the lower castes on an anti-Brahmin platform, seized power.

Photo

For Ramaswamy Sundararajan, 77, a retired marketing executive and a Brahmin who supports the B.J.P., the economy was his foremost concern. “The last five years have been very difficult. As people with inelastic income, we are the worst affected by inflation and a crumbling economy,” he said.

Mr. Sundararajan spoke over the constant noise that had taken over his middle-class neighborhood of Rajaji Nagar, a sign of the election campaign having reached a feverish climax.

Giant construction vehicles rolled past his house as workers rushed to complete a new, shiny road in time for the election. An auto-rickshaw, fitted with loudspeakers, beamed a recorded message from “Amma,” the popular name given to Jayalalithaa Jayaram, the chief minister of Tamil Nadu.

“We had a prime minister who wouldn’t open his mouth,” he said, almost shouting at the top of his voice to make himself heard, referring to Manmohan Singh of the Congress party. “Now we need a strict leader who would give us direction. We need someone who can take charge of us.”

Mr. Modi is also making an impact on the other end of the age and socioeconomic spectrum — that is, the state’s youth and urban poor. New supporters like Mr. Dorai have never been to Gujarat, but Tamil Nadu’s high literacy rate and, more important, the highest per capita television ownership in the country ensure that Mr. Modi has been able to package his economic accomplishments in his home state and appeal effectively to those at the lower ends of the social scale even in a state where his party has little presence.

Mr. Dorai said he followed Mr. Modi’s speeches, translated into Tamil, on television. He also happened to listen to Mr. Modi’s advertised messages on the radio every day as he drove.

Though Tamil Nadu is arguably a more successful economic model than Mr. Modi’s home state of Gujarat, scoring higher on measures of education and health care as well as growth, many have become fatigued with the two main Dravidian parties, and their supreme leaders.

M.K. Karunanidhi, president of the Dravida Munnetra Kazhagam, and Ms. Jayaram, head of the All India Anna Dravida Munnetra Kazhagam and the chief minister, have lorded over the state’s political landscape for the last 25 years, united by a visceral hatred of each other and locked in a seemingly endless battle of attrition. Both Mr. Karunanidhi and Ms. Jayaram have been accused of corruption in the past.

Much of the B.J.P.’s growing influence can be judged by the eagerness of the smaller regional parties to ally with the party. The Desiya Morpokku Dravida Kazhagam, the third-largest party in Tamil Nadu, has joined forces with the B.J.P. and three smaller regional parties, pitting their alliance against the two principal Dravidian parties.

The idea of Hindutva — the Hindu nationalist ideology that is core to the B.J.P. — has had wide appeal in India’s north and west but little cachet in the country’s south. Yet Tamil Nadu’s labyrinthine and unpredictable political situation means that those opposed to Mr. Modi do not face a simple choice, either.

Though both the Dravida Munnetra Kazhagam and the All India Anna Dravida Munnetra Kazhagam have stepped up attacks on Mr. Modi in recent days, in an attempt to sway the crucial minority vote in a state with a substantial population of Muslims and Christians, many voters believe that either of the two parties could join forces with Mr. Modi if the right circumstances arose.

The Dravida Munnetra Kazhagam and the All India Anna Dravida Munnetra Kazhagam have allied with both the Congress and the B.J.P. in the past.

A.R. Venkatachalapathy, a historian and professor at the Madras Institute of Development Studies, said that, despite railing against Mr. Modi in its electoral campaigns, he expected the two main Dravidian parties to side with Mr. Modi after the polls.

“Tamil Nadu has the most flexible political situation of any state,” Mr. Venkatachalapathy said. “Here, a vote against Mr. Modi may well turn out to be a vote for Mr. Modi.”