This article investigates the reasons underlying mainstream-niche parties switching in second-order elections. We generally claim that vote switching is mostly due to voters’ acknowledgment of issue competence assigned to niche parties and concomitant signalling of support for these issues to mainstream parties. Using data from the 2019 European Election Study we were able to demonstrate that: i) perceiving a mismatch between a mainstream party one feel close to and a niche party one considers to be the best at handling the most important issue leads mainstream-voters to switch to niche parties in European elections; ii) vote-switching to niche parties seems, to a great extent, to signal the importance of niche issues – such as the environment and immigration – to mainstream parties; and, finally, iii) mainstream vote loyalty does not hold when voters acknowledge niche parties’ higher competence.

--