Still no government in the UK, so I'll focus back home.
Part of the loss is a convention-based nomination system. Bennett might have had a tough time in a primary but would have had a fighting chance. Grassley is really, really lucky they didn't come after him, too. Maybe he was smart enough to see that, and "pull the plug on grandma" was a pre-emptive strike. That saved him his re-nomination, but cost him his brand and earned him a serious general election opponent instead of the usual token challenge he had at the time.
As for Bennett, he still has a shot at a write-in nomination, but he can't do a Lieberman because the independent filing deadline has passed.