I'm not sure if I agree, that will take some time to consider. However, a source for this "Later when asked about the Overton window, Lehman admitted that the

I'm not sure if I agree, that will take some time to consider. However, a source for this "Later when asked about the Overton window, Lehman admitted that the purpose of the Overton window was to convince potential donors of the role of think tanks in public policy." seems necessary.