Matthew Yglesias has an important article today in Vox: Policy and Politics. It is entitled Democrats are in denial. Their party is actually in deep trouble and it is well worth reading. Yglesias points out that although the Democrats have controlled the White House, that is almost the only thing they control in the nation's political system - they don't control either chamber of Congress, and the majority of state governors and state legislators are controlled by Republicans - and Republican control has been increasing even during Obama's terms in office (and perhaps because of his terms in office).
So although the liberal media talking heads have had a field day making fun of the current Republican disarray in the House, and the fact that Donald Trump currently leads in the polls for Republican presidential candidates, in fact the Democrats are in far worse shape nationally without even considering Hillary Clinton's continued troubles. If the Democrats somehow manage to retain the White House in this upcoming election, there is still little chance that they can advance much of their increasingly left-wing agenda. If they lose the White House they are almost completely locked out of government at the federal level, and in a majority of the state legislators.
I think much of the left-wing agenda, while emotionally appealing, is economically unsustainable, but I am not happy to see the Democrats in such trouble, because their weakness allows the more extreme right-wing to advance its agendas without effective opposition or debate.