However, every President has challenged Congress' limitations on the executive branch. This has been true since the beginning of our country. So many Presidents have questioned the constitutionality of the War Powers Resolution since it was passed.
On one hand, Congress has the ability to declare war and also the ability to fund it. However, the President has the power to command the armed forces which he has so that timely military actions can be decided on. This is why the executive is headed by a single person and not be a co-equal committee - they knew that such military decisions would be better if one person was responsible for it all rather than a group of people who may undermine each other.
I don't mind at all Congress starting to re-assert its authority over such things; however, I don't expect an adequate or long-term solution to this issue until the Supreme Court steps up and clarifies the guidelines on how such things should work between the President and Congress.