A primary role of political parties has traditionally been to filter candidates. It's literally their raison d'etre
Sanders wasn't even a Democrat. He switched solely to run in the primary. It's neither scandalous nor surprising that the DNC would try to put up barriers between him and the nomination.
If the RNC had done it's job, Trump would never have been allowed into the primary in the first place.
I don't know about that, but if they exist, they need to be stronger institutions that take more of an active role in picking/filtering candidates.
The introduction of the partisan primary has been an unmitigated disaster for our politics, by massively empowering the most zealous fringes within parties
Sanders wasn't even a Democrat. He switched solely to run in the primary. It's neither scandalous nor surprising that the DNC would try to put up barriers between him and the nomination.
If the RNC had done it's job, Trump would never have been allowed into the primary in the first place.