Indian Prime Minister Narendra Modi's shock ban on high-value banknotes will hit the war chests of his rivals before a key state election next year, sparking accusations that his strike against "black cash" will unfairly boost his party's chances.
That is despite widespread anger among millions of Indians forced to queue outside banks to change small amounts of old money for legal tender, possibly denting support for the ruling Bharatiya Janata Party (BJP) at least in the short term.
Opposition politicians are scrambling to redraft campaign plans ahead of the ballot expected early next year in Uttar Pradesh, a state of more than 200 million people which will be crucial to Modi's long-term plan for re-election in 2019.
The prime minister last week outlawed 500 and 1,000 rupee notes in a drive to rein in corruption and a shadow economy that accounts for a fifth of India's $2.1 trillion gross domestic product.
With no state election funding, illicit cash is the lifeblood for political parties that collect money from candidates and businessmen, and then spend it to stage rallies, hire helicopters and hand out "gifts" to win votes.
Spending on the Uttar Pradesh election is forecast to hit a record 40 billion rupees ($590 million), despite the cancellation of big notes.
Modi's demonetization drive has so far proven popular among increasingly aspirational voters who are tired of corruption, although views among the broader population and economists are divided over the efficacy and fairness of the move.
Opposition politicians have united to decry it.