NEW DELHI (Reuters) - For two decades, Lalu Prasad Yadav was a giant on India's political stage. He ran a state of 100 million people, he took charge of the country's massive rail network and his party was a crucial prop for the shaky coalition government in New Delhi.
Yadav managed all this despite a constant whiff of corruption around him. Indeed, he liked to thumb his nose at the law, riding triumphantly on the back of an elephant after a brief spell behind bars in 1997 as a crowd of admirers cheered.
Last week, a court sentenced Yadav to five years in prison for his part in a multi-million-dollar embezzlement case.
It was a landmark moment in a country where public disgust with corrupt politicians is finally starting to bite. Voters could throw the ruling Congress party out of power at the next general election, due by next May, for presiding over one of the most sleaze-ridden periods in the country's history.
An opinion poll in August said the party's parliamentary strength could drop to about 125 out of 543 elected seats. Currently it has 206, and rules with the help of coalition allies.
For graphic on India's corrupt politics link.reuters.com/hez53v
"Endgame of India's unclean politics," Kiran Bedi, a former police chief and now an anti-corruption activist, tweeted cheerily after Yadav was bundled off to jail last week.
The popular outrage has also spawned a clutch of new parties committed to ending the nexus between politics and crime, and - for the first time in quarter of a century - it has put corruption firmly on the agenda for national polls.
Probity has never been the strongest suit of the world's largest democracy. A staggering 30 percent of lawmakers across federal and state legislatures face criminal charges, many for serious crimes such as rape, murder and kidnapping.
Politicians and gangsters have long been bedfellows, not least because of the dirty money that fuels political campaigns. More than 90 percent of funding for the two main national parties, Congress and the Bharatiya Janata Party, comes from unknown sources, according to the advocacy group Association for Democratic Reforms.
Yet, only once in India's history has the public been exercised enough about graft to boot a government out for shady dealings. That was in 1989, when a kickbacks scandal over the purchase of artillery guns from Sweden's Bofors contributed to an election defeat for Congress and its then prime minister, Rajiv Gandhi.
The scandals have come thick and fast on Prime Minister Manmohan Singh's watch in the last few years.
There was a huge scam over the sale of the 2G mobile spectrum, which Time magazine listed as number 2 on its "Top 10 Abuses of Power", behind the Watergate scandal. New Delhi's botched hosting of the 2010 Commonwealth Games led to dozens of corruption cases, and then the government was hit by a furore over the allocation of coal deposits now known as "Coalgate".
All this has prompted the emergence of an anti-corruption movement, one that swelled in 2011 with huge protests led by Anna Hazare, who styled himself as a crusader in the mould of independence hero Mahatma Gandhi.
The outcry has continued since then, rattling the government, in part because much of it comes from the urban middle-class, a traditionally apolitical bloc whose sudden engagement could shatter electoral calculations.
A Lowy Institute poll of Indians in May found that 92 percent thought corruption had increased over the past five years, and even more believed that reducing corruption should be a top priority for their government.
A newly formed party, the Aam Aadmi (Common Man) Party, has tapped into the angst over sleaze. The AAP chose a broom as its symbol, to suggest it is sweeping the muck out of politics. In a video game launched last week, the party's leader navigates the corruption-plagued streets of the capital wielding a broom.
An increasingly activist judiciary has added to the clamour to rid politics of criminals.
In July, the Supreme Court decreed that lawmakers convicted of a serious crime would immediately forfeit their seats, closing off a loophole that had allowed politicians to stay on during appeals, which can drag on for years in India.
Last month, the court ordered the Election Commission to introduce a "none-of-the-above" choice for voters, allowing them to reject unsavoury characters instead of choosing the best of a rotten bunch.
The AAP, which is expected to disrupt the usual two-party race in a Delhi state election next month, is just one of several parties to be set up on an anti-corruption platform.
Among them is the Nav Bharat (New India) Democratic Party of Rajendra Misra, who gave up various business interests to join public service seven years ago. He worked with the main national parties to improve policy and governance, but was disillusioned by the venality around him and finally decided to go it alone.
"India isn't a poor country. It's a poorly managed country," says Misra, who is planning to stand in next year's election.
There will be many election first-timers like him: young white-collar working professionals challenging a system where political seats are mostly occupied by old men and handed down to next generations like family heirlooms.
The upstarts have their work cut out for them in a country where votes are still cast along community lines rather than by ideology, and where mainstream parties are flush with cash.
Milan Vaishnav of the Carnegie Endowment for International Peace says the chances of a criminal candidate winning an election are three times better than others, and money is not the only explanation.
"Candidates often use their criminality as a sign of their credibility to protect the interests of their parochial community," Vaishnav said, saying that voters sometimes choose criminals not despite of their criminality, but because of it.
Shekhar Tiwari, a co-founder of the Nav Bharat Democratic Party, recognises the enormity of the task facing the anti-corruption challengers. "Some of what we say sounds like a dream. But if we don't dream, nothing is possible," he says.
Still, a recent drama in the Congress party, which is led by Nehru-Gandhi dynasty, showed which way the wind is blowing.
Prime Minister Singh's cabinet issued an executive order allowing convicted lawmakers to continue to hold office and stand in elections, in essence defying the Supreme Court. Critics said the move was aimed at shielding allies - such as Yadav - whom the Congress may need to form a ruling coalition after the elections.
As brickbats flew, Rahul Gandhi - the Congress party's likely candidate for prime minister and scion of the dynasty - stunned and embarrassed his own colleagues in a rare public outburst, calling for the order to be "torn up and thrown out".
A few days later, humiliated and looking divided, the government withdrew the decree.
"Rahul did that because he is convinced that this would destroy the tattered remnants of Congress' credibility," said Prem Shankar Jha, a political analyst. "Had this gone through, Congress would no longer be a victim of the criminalisation of politics but would be a patron of it." (Editing by John Chalmers and Raju Gopalakrishnan)