I asked this question earlier: Which is more dangerous to US democracy: Far-left or far-right ideologies? and after thinking about the comments received, I realized that I should start with some underlying questions. Mainly, what measures are commonly used to estimate the political power of an organization? For example, in a history of health insurance in the US I recently read, the author claims that the power of the American Medical Association has decreased since the 1930s. In general, given that the indicators of political power might be very different depending on the group of interest, what would one look at to make such an estimate of of any organization, be it an official political party or the girl scouts?
I did see this post: What methodologies of measuring the power of the state are researched today? but it seems to primarily address power at a national/global level.