What? That is so not true I don’t even know where to begin. The President, of course, has some input into what the budget will be but we have seen plenty of times that Congress can and will flex their power when the parties of the Congress and President do not match.
The president proposes the entire budget, and can veto the entire budget regardless of which party is in power. Of course Congress has immense influence and you also can't pass a budget they don't agree with. That doesn't change that not only does the president matter (the claim I'm refuting), they are the most important single person that matters, by design.
