This is not Barack Obama’s fault and it’s not exclusively George W. Bush’s fault. It’s what comes from decades of unserious negotiation with bad actors.
Couldn't it also be North Korea's fault? After all, the North Korean leadership has endured near total isolation to advance its long range missile and nuclear weapons programs. It's clear that those programs are integral to the survival of the regime.
Despite the bluster from neoconservatives on the issue, both parties, once in power, have shown very little willingness to remove Kim Jong Il from power. (Once out of power, of course, it's back to bomb's away.) Everyone is invested in the status quo - as distasteful and indeed, dangerous, as it currently is because there's an acute understanding that the alternatives could be much, much worse.