It’s not a war, it’s a special military operation.

The president isn't empowered to declare war, but as Commander in Chief he is empowered to send the military anywhere he wants and start whatever "conflict" he wants, for whatever reason he wants, including no reason whatsoever. After which Congress can retroactively declare it a war if they so choose. But the US hasn't fought a declared war since WW2, because declarations of war don't really mean anything when the missiles have already been fired and the bombs have already been dropped.

I hate Trump as much as anyone with a moral core should, but the President's capacity for creating arbitrary military violence and expenditure has always been unchecked.