I mentioned in a June 28 post that Democrats had made a number of tactical mistakes that were coming home to bite them now. In that regard I recommend Mark Thiessen's article today in the Washington Post (reprinted from the Chicago Tribune) entitled Democrats are powerless to block Trump's Supreme Court nominee - and have no one to blame but themselves. Thiessen traces the Democrat's series of errors back to the unprecedented 2001 filibuster of Miguel Estrada for the U.S, Court of Appeals, under the Bush administration, apparently because they didn't want the Republicans to get the credit for eventually appointing the first Hispanic to the Supreme Court. Thiessen then traces the series of subsequent errors they made which have left them largely powerless now to prevent Trump from naming whomever he wishes to replace the retiring Justice Kennedy, and to fill any further openings that might occur before the midterm elections, and even after if the Republicans maintain control of the Senate, as seems likely.
It does seem to me that Congressional Democrats have been remarkably incompetent since Trump was elected. There have been a number of opportunities for them to offer Democratic votes in return for concessions on issues they care about, but they have adopted such a obstructionist position, even on issues they supported under Obama, that they have wasted the opportunities.