Just want to point out that neither party is representing the majority of American people and any claim of "mandate" is over-blown here (or any recent election really.)
If either of the major parties appealed to the majority of voting-eligible American adults who didn't vote, enough to get a sizeable minority of their votes, they would be a dominant party in the same way the Democratic-Republicans were in the Era of Good Feelings, the Republicans were for decades after reconstruction, and the Democrats were in the New Deal era.
This should be what the Democrats focus on solving in the next few years. How can one capture this large, majority, disaffected population? What are the issues they care about? I can guarantee it is not the things either major parties focus on.
