Overton’s Window refers to the range of acceptable topics that can be discussed politically. The window is changed not when politicians change their ideas but when ideas change in the society that elects them. The Left wing is particularly good at changing the window. Gay marriage is a good example.
Consider gay marriage, a subject once so far outside the mainstream that less than 20 years ago, Republicans and Democrats united to pass the Defense of Marriage Act to define marriage under federal law as the union of one man and one woman. Now? That view is such an anathema that it’s difficult to get — or retain — a job in entire sectors of the economy if you openly hold to the traditionalist position on marriage.
Donald Trump has been able to address some of the subjects that were unacceptable to discuss previously because American society has changed and is now more receptive.Progressives until recently controlled societies views on subjects like Islam, immigration, border control and groups like Black Lives Matter.It was socially unacceptable to criticise any of these three. Being white was something to be ashamed of and being patriotic or nationalistic was viewed as racism.