as I understand it, populism is when you exploit 'popular' causes to get a mass backing to bring yourself into, and to stay in, power. It is opportunistic, 'goal justifies means' philosophy.

So, you don't really have orinciples or a cause, apart from 'I should be in charge'. It also means voters, if they are capable of judging that, cant really trust you, because you will switch causes whenever it suits you.

In my own country, I could name politicians who always carried the same color as the reigning political movement, and who would switch when the winds change, because their real principle was 'be on the winning side'.