I don’t believe that political calculation is wrong.
If you change your position in your campaign for political office, you better hope that it’s the better one. Because it will be the job of the activist to either hold you to it or bring you down on it.
I don’t think Trump is wrong to change his opinion from last year on Canada’s single-payer healthcare. I think he’s grievously wrong for having the wrong position on it, and for flat-out lying about Canada in the process.
I don’t think Clinton is wrong to change her position on fracking. I think it’s good that she has changed it to a nuanced opposition, but she may have been misinformed about its supposed benefits in the first place.