All of this can be traced back to losing the election, which only happens because they rigged it for HRC. HRC was not only unlikable, but they turned off a large part of their own base that supported Bernie because of how the primary was rigged against him. Those people stayed home or voted third party, leading to Trump's victory. A perfect example is Michigan... I heard on Bill Maher after the election that if you just take the ballots that voted straight-ticket Democrat but left President "blank", ostensibly because they couldn't bring themselves to vote for HRC, that it would've flipped the state in her favor.
So they put themselves in this situation by being corrupt, costing themselves two SCOTUS seats that taken together have the ability to undo decades of liberal policy.
In a desperate attempt to stop Kavanagh confirmation, they withheld information for many weeks trying to run out the clock to the mid-terms where they could maybe take back the Senate. These tactics are galvanizing the Right... which until this point was very split and parts of it very displeased with Trump... and moreover it's rubbing a lot of people in the center the wrong way. It has potential to not only fail in main goal of preventing a conservative court, but totally backfire and cost them big in 2018 and 2020 when they had been surging in special elections and polling since Trump's election.
And it can literally all be traced back to the decision to rig a primary for a corrupt, unlikable person.