Donald Trump appears to have graduated from a flash-in-the-pan infatuation to a genuine existential threat to the GOP as we know it. He's bucked the Republican establishment's preference for immigration reform, coming down hard against undocumented immigration, and even for lowering documented immigration. He's sanguine about hiking taxes on the very wealthy, and he's promised to defend Medicare and Social Security from cuts. This led reform conservative Ross Douthat to term Trump a "class traitor" in the mold of Franklin Roosevelt.