I'm going to say that Barack Obama's big Middle East speech almost certainly goes down in the "didn't matter" category -- and that's not a criticism. Presidential speeches can matter, but this one wasn't likely to; he was unlikely to present new proposals, he didn't present new proposals, and now we'll move on.
I'm confident that Newt Gingrich's Very Bad Week didn't matter to the 2012 presidential race. Let's see...I guess Mike Huckabee's announcement was technically during the "What Mattered This Week?" week, and that one, I think, does matter. Huck was one of a handful of plausible winners, now a handful minus one.
And then we had the Liu nomination going down in the Senate. I do think that one was important, but I'm just not sure yet, as I said earlier, exactly what it signals. I'll certainly be watching.
What am I missing? What do you think mattered this week?