big and fight hard. not when we dream small and quit before we get started. >> reporter: shrinking to seven in december thanks to the polling thresholds. no question defined the democratic primary fight this year more than this. do voters want an ideology revolution or a candidate focused on relief from donald trump. at top of the field, bernie sanders and elizabeth warren are the revolutionaries promising sweeping change and former vice president joe biden and mayor pete buttigieg and senator amy klobuchar say in kremental change is more realistic. nowhere was this more on display on on obamacare. >> 71% of democrats support medicare for all. >> stay tuned for the answer in 2020. >> reporter: 2019 started with a new class of house democrats.