Well the title spoils the element of surprise here, but this will be brief anyway. Sports analogies are quite useful, they are employed all the time (with the possible exception of the fashion industry). I often like to use these myself and when I do I stay within my comfort zone, the NFL. Being the chauvinist prick that I am I confidently assert that it is the only sport that matters.
Now... , the democrat party, in football terms are a team in the NFL. I won't attempt to identify them with a specific franchise or with a specific historic comparison. They are the team who entered the final month of the regular season with a two game lead in their division. Their nearest division rival had beaten them in the first of their two contests, but they had remained apace with that two game lead. The way that the schedule aligned had this division leader with an easy home field contest against a cellar dweller for game 15 and the finale vs. their division rival, also on their home field.
They are that team who then won two more, then choked to the cellar dweller in week 15. This sets up the game, in the season finale, where this division leader, win or lose, is still making the playoffs. If they win they win the division and possibly a first round bye in the playoffs. If they lose then they must enter the playoffs in the wild card round. In 2016 the democrats lost that season finale.
The 2018 midterms are the wildcard round. This time they either win or they go home. And they know it. The next 60 days promise to be an absolute circus.