Scoop: House Democrats want changes at the DCCC after $500,000 blunder in Arizona

House Democrats are publicly and privately pushing for changes at the Democratic Congressional Campaign Committee after it spent more than $500,000 backing a failed primary candidate in Arizona. Why it matters: The House Democratic campaign arm has faced persistent criticism this year from its members for getting more heavily involved in primaries than in past election cycles. "I don't think they should get involved in primaries — I've said that before, I've said that directly to them," said…