No country actually declares war anymore. From Wikipedia:

Declarations of war have been exceedingly rare since the end of World War II.[3][4] Scholars have debated the causes of the decline, with some arguing that states are trying to evade the restrictions of international humanitarian law (which governs conduct in war)[4] while others argue that war declarations have come to be perceived as markers of aggression and maximalist aims.

That part of the US Constitution is irrelevant nowadays and should long have been updated to require any foreign (or domestic) military operations to be first approved by Congress, not just declaring war. Doesn't make your point of Congress granting ever more rights to the President irrelevant though.