President Trump used his State of the Union address to prod Congress to codify his "most favored nation" plan to bring U.S. drug prices in line with what other developed nations pay.Why it matters: Trump made clear he is comfortable making health care a prominent feature of Republicans' midterm election plans, despite misgivings among some in his party and the GOP's vulnerability on affordability.The gambit could backfire if people don't actually see a change in their own costs, Axios' Caitlin O...