To further poison the national discourse

The more debates they have, the more they can talk up privatizing everything, sucking the life out of every government function except the military, putting foxes in charge of every henhouse, turning back the clock on every good thing the Democrats have done, removing any and all environmental protections, throwing everybody but privileged white males under the bus, etc. etc.

Then these destructive talking points and lunatic ideas get discussed with gravitas on "news" programs and written about on editorial pages and web sites, and they gradually become part of the landscape of what is possible.

The idea is to make their sick "ideology" seem normal to Americans, so that even as the most extreme candidates slough off one by one like so much worm flesh, their toxic ideas burrow further into the national cranium.

So, for example, maybe abolishing the Department of Education doesn't happen, but diverting more public funds to private institutions does.