A Comparison of Threats

I'm a little confused. A decade ago, when Bush wanted to go to war against Iraq, the liberal outcry was that (a) the supposed "weapons of mass destruction" hadn't been proven to exist and (b) the Iraq government had not made any threats against the US or its allies.  Now, when Obama is urging us to attack Syria, shouldn't we apply the same tests?

Syria has been accused of manufacturing and using poison gas against its rebels. The report has been disputed and there are counterclaims that it is a rebel ruse. Such a weapon, assuming missile or terrorist delivery, could kill thousands of people at once. However, Syria has never threatened to use such as weapon against the US or any of its neighbors.

In contrast, Iran is well known to be developing nuclear materials and, despite its claims to the contrary, is probably working on nuclear weapons. Although it has a limited missile capacity, it is connected to terrorist organizations that could deploy "dirty" or fission bombs that could kill tens to hundreds of thousands of people. Its leaders claim to have no such goals but have repeatedly threatened to annihilate Israel and have called the US "the great Satan" and taken US citizens as hostages.

The status of North Korea is even more threatening. Its leaders boast that they are developing nuclear weapons and missiles with which to deliver them. They have explicitly named South Korea and the United States as their enemies, which is reasonable since they have never formally ended their war against us.

Let's put all this on a graph. The units are arbitrary and the estimates are guesswork but the general trend is obvious.   

If the situation is Syria is sufficient to provoke US action, aren't the situations in Iran and North Korea even more urgent? I challenge Mr. Obama to explain the grounds for his choice.