I was stationed at Vandenberg AFB for 5 years and saw plenty of launches. Looks like a missile to me. If If I were to guess, it looks like an air defense type, maybe a Standard missile, which is the Navy's mid-to-long range interceptor (the ER, or extended range, is a pretty good size rocket). Doesn't look like it could be from Vandyland, as that is a bit north of the area it appears to have com from, so a ship-launched AAA rocket makes the most sense. They don't do test sub-launches of tomahawks or harpoons in that area, and NEVER do SLMB launches without a lot of pre-notification (for what should be pretty obvious reasons). I don't believe it is a foreign launch, as that would be an insanely dangerous move by a foreign power. Of course, it could have been a terrorist group, one that went wrong perhaps, as it appear to have headed out to sea rather than over land.
That area has plenty of radar coverage, as there's so much air traffic in that area, and it seems odd (mysteriously so) that no ATC reports have been forthcoming. We've also seen no upgrading of the threat levels in this country (if it were a terrorist attempt, there would be), so my best guess would be an accidental launch. That in itself is a distrubing enough scenario.
