Senate Republicans today blocked an independent, bipartisan commission to inquire into the January 6 Capitol riot. This will not prevent Congress from conducting its own investigation, but it will be an openly partisan probe rather than one that offers the appearance — and maybe the reality, depending who you ask — of fairness and balance. It’s worth thinking through what purposes a commission would serve.

On the one hand, we do not need a commission to publicize the events of January 6. We do not need a commission to draw conclusions about public events (such as the actions of Donald Trump …