No issue threatens to break President Biden's fragile Democratic coalition like Israel's response to the Hamas terrorist attack. Why it matters: Infighting is spreading, slowly but meaningfully, at every layer of the Democratic Party over Biden's full-throated support of Israel. It runs much deeper than college campus protests or caustic comments from elected officials. Step back and survey the split: Many liberal Jews are furious that so many progressive Democrats aren't more outraged by the slaughter of family and friends back in Israel. Some are threatening to leave the party. Pro-Palestinian Democrats are outraged at the rising death tolls in...