A fight is breaking out inside the Democratic Party over Israel, party loyalty, and the class divide splitting its voters — bad news for the old establishment.

• Senator John Fetterman told Jon Stewart that Israel is his red line: he would leave the party over it even if he agreed on everything else, drawing sharp criticism for treating support for a foreign country as a loyalty test.
• Critics say pro-Israel figures conflate criticism of Israel with hatred of Jews to shield it from any pushback, and argue most "anti-semitism" flagged in the U.S. is actually anger about Israel, not real threats to Jewish Americans.
• Abdul El-Sayed's narrow Michigan Senate primary win shows a growing split: college-educated and higher-income voters back the left insurgent, while less-educated and older Black voters stick with establishment candidate Haley Stevens.
• The key divide is education, not income — Democrats who read tend to break left on Israel, while TV-watching voters absorb a more pro-Israel frame from mainstream cable.
• AIPAC spent big money falsely tying Stevens to Obama's endorsement, a tactic that works because establishment-leaning voters trust those cues.

Outlook: Expect the left's class-focused, grassroots playbook to keep denting the party establishment, but breaking the loyalty of older Black Democrats remains the wall it has not cleared.