Tonight, the first Democratic debate of the election season will kick off. With two GOP debates in the rearview mirror, the first of the debates on the left should offer an opportunity to see how the candidates will distinguish themselves. In particular, one issue that’s been largely absent (at least from the GOP debates beyond “repeal and replace”) is health care. In this coming debate, and in the later GOP debates, the moderators ought to seek out the candidates’ positions on a slew of health care issues.