Rep. Alexandria Ocasio-Cortez, D-N.Y., attempted to make a case for universal health care on Thursday after a tense confrontation over the HIV prevention drug known as PrEP. During a congressional hearing, Ocasio-Cortez pressed Gilead Sciences CEO Daniel O'Day on why his company's drug -- Truvada for PrEP -- cost so much more in the United States than in Australia. She later answered her own question on Twitter, saying that the U.S. health care system was to blame. "Spoiler: Because Australia has universal health care," she tweeted. During the hearing, O'Day responded to Ocasio-Cortez by noting how the drug was under...