This essay was published a while ago, but I only read it today and thought it was an interesting idea:
The summary is that if you support a policy that is not currently politically feasible, working to popularise it with the general public is a good and beneficial thing to do, and can result in moving the Overton Window enough for it to be passed. On the other hand, supporting an even more extreme policy in the hope of making your favoured one look moderate by comparison is not a good idea, most especially if you don’t actually think the more extreme policy is a good idea. Proposing unnecessarily radical, and particularly unsound, ideas is likely to lead to a backlash that could make it even more difficult to get support for your less extreme policy.
He gives examples of ‘Defund the Police’ on the left, which seems to have helped torpedo more moderate efforts at police reform, and Trump’s anti-immigrant rhetoric, attempts to build a wall etc, which has created far more opposition to his clampdown on asylum seekers and attempts to deport illegal immigrants than there was to Obama doing those things.
I’m not sure I’m convinced by this example; I think the opposition has more to do with how Trump is going about implementing his policies - eg ignoring due process - than with his suggesting even more outrageous ideas. But there must be other examples, since Trump is the king of throwing out crazy, extreme suggestions. Have these helped normalise his less crazy, but still previously outside-the-Overton-Window ideas, or the opposite?
This comment on the article suggests a parallel:
Perhaps it’s similarly true that supporting policies that are only a little more extreme than yours is helpful, but if you push it too far, it can have the opposite effect. Or maybe it’s the overall distance from the current Overton Window that matters? If your policy is already far from the edge, it’s better to avoid anything even a little more radical.