Bernie Sanders and the progressive wing are clashing with Hakeem Jeffries and establishment Democrats over primary endorsements — good news for progressives, bad news for the party's old guard.

• Sanders backed a progressive challenger over a conservative Black Caucus incumbent, and Jeffries called him to warn him off, but Sanders wouldn't budge.
• Sanders has endorsed more than 90 candidates this cycle, and 42 of the first 60 to hold elections have won — over two-thirds.
• Establishment Democrats say his primary fights waste money that should go against Republicans, and are using candidate Graham Platner's exit to question his judgment.
• Two Michigan races are the big test: progressive Abdul El-Sayed vs. pro-Israel moderate Haley Stevens for Senate, plus a three-way House race.
• Israel is a real dividing line — El-Sayed's supporters say they won't vote for Stevens, who is openly pro-Israel, in the general.

Outlook: Michigan's late-summer primaries will signal whether the progressive surge keeps rolling or the establishment holds the line.