Bob Zimmerman has been reading the GAO report (as have I), and has some thoughts:

…my impression here is that NASA is trying to impose its will for political reasons, not safety, in order to make the commercial program as ineffective as SLS/Orion has been. And the proof of this is NASA’s decision this week to consider flying humans on the very first test flight of SLS. If NASA as an agency really cared about safety like it claims in this GAO report, it wouldn’t dream of flying an untested SLS manned. While the GAO report can only point to some specific and somewhat limited issues faced by Boeing and SpaceX, SLS remains completely unknown. Unlike Atlas 5 and Falcon 9, it has not flown once. None of its components have been tested in flight, and to ignore this basic fact and fly it manned [sic] the first time is absurd.

No, it appears to me that NASA and certain members of Congress are trying to manipulate things to save SLS. Their problem is that SLS simply stinks. It has cost too much to build, it is taking too long to get built, and it remains an untested design that has a very limited value. Even if this political maneuvering gets SLS up first with people on board, and that flight does not fail, SLS will still stink. Its second flight will still be years away, while the commercial capsules will be able to fly numerous times in the interim, and they will be able to do it for a quarter of the price.

The worst aspect of this political maneuvering is that it is harming the American effort to fly in space, for no good reason, and might very well cause the death of Americans. Instead of getting Americans launched quickly on American-built spacecraft, these political games are forcing us once again to consider depending on the Russians for an additional few more years. Considering the serious corruption and quality control problems revealed recently in Russia’s aerospace industry, we should not feel save launching Americans on their spacecraft. And we certainly shouldn’t feel safe launching them on SLS during that first test flight.

It’s a political stunt. Instead of trying to win a race with the Soviets, they’re trying to win a race with private industry, while handicapping the competition. There is only one realistic “back up plan” for ending out dependence on Russia. Start flying without “certification,” while making clear the risk.

[Late-afternoon update]

Gwynn Shotwell: “The [heck] we won’t fly before 2019!”

I’m guessing that Marcia bowdlerized her, and she used some other word starting with “He.” And it’s not “helium.”