THE denial by Manmohan Singh, India's prime minister, sounded categorical. He claimed, on March 18th, that no one in his ruling Congress party, nor in his government, had paid any bribes to opposition MPs to get support in a crucial vote of confidence, in 2008. Yet the opposition parties in India's parliament, on both the left and the right, were furious over the issue, disbelieving him, calling for him to resign and lamenting that “shame” had been brought upon India's reputation.

There's plenty of shame to go around. The corruption saga bedevilling politics in India has reached another extraordinary stage. The latest fuss follows the publication this week, by the Hindu newspaper, courtesy of WikiLeaks, of details of a cable transmitted by American diplomats in 2008. Apparently the Americans were told by someone in the Congress party that chests filled with cash, some $25m, stood ready to be spent on swaying the votes of opposition MPs, to help ensure the confidence vote would be won. The American interest was acute: the vote had been called over efforts to pass a bill on nuclear power, which was seen by many on the left in India as a sop to potential American investors. To the Americans—and to India's rulers—the bill was vital, part of a deal between the two countries which would allow a big expansion of much-needed civilian nuclear power plants in India. As important, it enshrined much warmer relations between America and India, which infuriated India's Communists, and some others.

Mr Singh's government has been rocked by a series of corruption scandals and is struggling to come up with any effective response. In the course of a few months, rows have erupted over graft in the Commonwealth games in Delhi, a property scandal in Mumbai, and the appointment of an anti-graft commissioner, P.J. Thomas, who had been charged himself for corruption. (Mr Thomas has been forced to step down, by the Supreme Court.) Most striking, however, is a telecoms scandal, over the dubious sale of 2G spectrum, in which the minister in charge, A. Raja, allegedly forfeited some $39 billion in potential revenues. Mr Raja was sacked and then arrested. His close assistant, Sadhick Batcha, was found dead this week, apparently the result of suicide.

All this is taking a heavy political toll. Mr Singh looks burned out. No one suggests he is personally corrupt—indeed he is very widely respected as a liberalising force—but he seems unable to get a grip on problems around him. If there were an obvious, strong and clean individual waiting to replace him as prime minister, Congress might now be getting ready to engineer a change. Mr Singh is 78 years old and is widely expected to have left office before the next election, scheduled for 2014. But Congress seems unwilling to act now. Rahul Gandhi, the young leader-in-waiting, shows little appetite yet for the job. In any case, the high command of the ruling party probably prefers to keep the scion of India's ruling dynasty as unblemished by the grind of daily politics as is possible, before the general election. An interim leader is possible, perhaps Pranab Mukherjee, the finance minister, but it is not clear that he would be any better than Mr Singh at fending off the opposition's allegations of graft.

Instead the ruling party has a strategy of hoping for the squalls to pass. A series of important state elections are pending in the next few weeks, and Congress—despite the corruption woes—is hoping to do well, especially in West Bengal and Kerala, at the cost of the left-wing parties. At the same time, Congress hopes that the Communist parties and the Hindu nationalist Bharatiya Janata Party (BJP) will be unable to co-operate for long. In the background, most voters may yet be more concerned that the economy keeps galloping, now at a rate of 9% GDP growth. Yet his mounting political problems guarantee that these will be gloomy days indeed for Mr Singh.