“Journalists need to stop inviting politicians on their programs if they refuse to answer questions. Otherwise it’s not news – it’s just a game of dodgeball.”

That might work. Or their bosses could stop giving away live airtime and have all such interviews recorded. Inform the interviewee that non sequiturs will not be aired. And surround any answers with fact checking and context. It’s more work, costs more money, and doesn’t fill up gaps in scheduling so well but it may more effectively inform the public.