He stoked the hyperpolarization of American politics to make the Obama presidency as dysfunctional and paralyzed as he possibly could. As with parliamentary gridlock in Weimar, congressional gridlock in the US has diminished respect for democratic norms, allowing McConnell to trample them even more. Nowhere is this vicious circle clearer than in the obliteration of traditional precedents concerning judicial appointments. Systematic obstruction of nominations in Obamas first term provoked Democrats to scrap the filibuster for all but Supreme Court nominations. Then McConnells unprecedented blocking of the Merrick Garland nomination required him in turn to scrap the filibuster for Supreme Court nominations in order to complete the steal of Antonin Scalias seat and confirm Neil Gorsuch. The extreme politicization of the judicial nomination process is once again on display in the current Kavanaugh hearings.
Source:
https://www.salon.com/2018/10/05/historian-of-nazism-explains-why-gop-senate-leader-mitch-mcconnell-is-the-gravedigger-of-american-democracy_partner/