This is either too clever by a half or under-clever by a whole lot. You decide:
If it is saying, as it should be, that these are political and not legal fights, that the public and congress already know everything they need to know to make a judgment about whether the NSA and US Attorneys policies were good ones, and that the advice the president gets from his advisers is no more Congress's business than the advice Senator Leahy gets from his, then that is the position they should stick to.
I almost feel ridiculous pointing this out, but, see, the NSA and US Attorney policies aren't exactly the national security and judicial appointee equivalents of, say, Medicare Part D. The NSA policy was in and of itself a crime and the US Attorney policy was only able to move forward because a bunch of advisers broke the law. Yes, there is a political side to all of it, too. If the investigations hurt Democrats politically, I sort of doubt they'd pursue them so intently. But whenever a president (from whatever party) treats the Constitution like a piece of food stuck in his teeth, it should be incumbent upon the Congress (also from whatever party) to investigate him thoroughly.