Hate to say it, but they're wrong. Presidents have been fighting wars without congressional approval since John Adams and Thomas Jefferson. Which is one reason why someone like Obama should never be elected in the first place.
Here is a good analysis of the power of the President and committing the military without Congressional approval. And the avoidance of the court in clarifying the issue as far as the Constitution is concerned.
http://www.daveross.com/war.html
It is clear that the President has the power to defend the nation if attacked without a prior Congressional approval.
It is also clear that the Constitution states the only Congress can “declare War”.
The Fed Gov has set some horrible precedents concerning this. Most, but not all under Dem administrations.