LOS ANGELES (AP) — U.S. House battles are taking shape that could tip the balance of power in Congress. In the heavily Democratic California, Republican House members are facing tough challenges in several districts. Republican U.S. Rep. Steven Palazzo of Mississippi was forced into a runoff after a congressional ethics watchdog raised questions about his campaign spending. In Montana, former Interior Secretary Ryan Zinke was in a tight race for a chance to capture a new U.S. House district. The contests were among primary elections across seven states Tuesday that set up November showdowns in dozens of races.