By constantly moving to the left, the left is exerting control of the political space, defining the Overton Window in terms of its own political leanings
The moderate solution is deeply seductive for Republicans, who see their opposition sliding to the extreme left and believe that they can sweep up the middle by just moving a little to the left. All they have to do is moderate their position on X, Y or Z, and they will win over all the unaffiliated voters who are a natural fit for their common-sense policies.
