Who Has the Right to Engage the US in War?

Open email to Rep. Neugebauer and Senators Cornyn and Cruz (TX):

Dear Rep. Neugebauer and Senators Cornyn and Cruz,
    The Washington Times says the Obama Administration and Russia reached a deal Saturday to compel Syria to account for and eventually destroy its chemical weapons arsenal, leaving open the possibility that the UN could authorize sanctions or military action for future violations.
    Whew! We are off the hook, at least temporarily! I was shaking in my boots on the possibility of Pres. Obama declaring war on Syria by a military attack. We have had enough stupid wars, and this would have been the leader in stupidity. President Assad of Syria has done nothing to disturb US interests anywhere in the world. What he has done involves his personal handling of an internal Syrian situation, which is none of our business.   
    However, I'm still disturbed. Pres. Obama had us on the brink of war for no justifiable reason, and he could do it again. He says he has every right to take unilateral action on foreign military matters without any consideration of Congress. I personally don't see that anywhere in the Constitution, but perhaps I'm missing something.
    Whether I am right or wrong, Congress must take action to clarify that situation, so that we don't engage in another war through some stupid action by the President. Some might say that a situation may require fast action, which the President could take, while Congress would be too slow. That's not true. Referring to World War II, the Japanese attacked our naval fleet Pearl Harbor on December 6. I'm not sure when the US actually declared war on Japan. It might have been almost immediately by Pres. Roosevelt, but if so, it was not necessary. The attack was over and there was plenty of time for Congress to retaliate with a declaration of war.
    I've said before that war is not a sporting event. By its definition, it is a terrible event. People kill each other, and as I have said separately, that killing should be done by any effective means to eliminate the enemy.
    But now, it is up to Congress, not the President, to define the conditions under which war will be declared by the US. In this consideration, let's also remember that any military attack against a foreign entity is an automatic declaration of war.