That is indeed how it is supposed to work. But things haven't exactly been working like they're supposed to lately.

For FY26, when we had a PBR proposing massive cuts followed by a government shutdown with a long stretch where NASA didn't know what their real budget was going to be, we saw a bunch of layoffs and project cancellations in preparation for a budget that might resemble what the president was requesting. Whether or not that was legal is in question:

https://democrats-science.house.gov/imo/media/doc/SST%20Mino...

That is true, but in all fairness, every politician has at one time, or another requested all sorts of nonsense to appease the base, not just presidents hence the term "political lobbying". If you look up the definition of 'politics," it's the method or strategy: sometimes used to describe the tactics, schemes, or "art" used to gain influence, sometimes carrying a negative connotation of manipulation or intrigue. Everybody has done it since the beginning of time :|

Congress also declares wars, and we know how well that has worked out for everyone.

First year civics: the legislative branch passes the budget, the executive branch is the one that actually spends it. Or doesn’t, in which case you have a constitutional crisis.

This same president wanted a Mars landing by 2028.

It has been 30 years since Congress last passed a budget.