The Swiss Nemo won the European Song Contest in Malmö in May and the idea is to hold next year's competition in Basel.
The canton has provided economic guarantees of 37.5 million Swiss francs, equivalent to approximately 450 million Swedish kronor.
However, Switzerland has a system of direct democracy and the Christian right-wing party EDU has requested a referendum to stop the economic support.
If the economic support is rejected, the arrangement will have to be significantly scaled back. Instead of a ten-day festival, it will be a single TV broadcast on Saturday evening and no side activities. The organizers also estimate that the two semifinals that select the final entries would need to be scrapped to make ends meet.
