If Congress actually cancels the SLS rocket, what happens next?

The US government abruptly canceled major NASA programs like the SLS rocket, Orion spacecraft, and Lunar Gateway due to a "skinny" budget proposal from the Office of Management and Budget. Opinions on these cancellations vary widely; some fear it might eliminate future human spaceflight missions, while others see it as necessary for long-term savings. The decision hinges on Congress's support, which has backed these programs for decades but is now reconsidering them under budget constraints to avoid expensive upgrades with unclear purposes beyond Lunar Gateway.