I think it's obvious. It's clear—manifestly clear—that sanctions have not worked. The long history of sanctions has not worked to prevent North Korea from continuing to develop a nuclear weapons capability. The classic statement about sanctions is that they must be part of a larger strategy, that the best they can hope to do is slow things down, and that in the meantime you should be pursuing an effective solution. In this case, I'm arguing for a negotiated solution.
It was interesting in the Iran case. Again, Iran is an example of sanctions and a broader negotiating strategy. One way that sanctions can bite a bit happens where the government is answerable in some way to the public, such as facing an electorate, so that the economic impact of the sanctions is felt by the public and they let the government know that they don't like it. That of course doesn't apply in North Korea at all.
Sanctions, however, are important. I certainly wouldn't argue that the sanctions be lifted. They're important in a broader context to send a message to other states that this is not a cost-free exercise. North Korea has an incredible tolerance of sanctions because the regime is all-powerful. As the Russians have said, the North Korean regime would let its public eat grass before they would give up.
However, it's still important that the sanctions stay on. This is a statement by the international community that this behaviour is not acceptable, and it's also important for the broader messages being sent, but no, they manifestly fail to stop North Korea. That's why we need to try other things, and I'm urging diplomacy.