How do I keep defending work that keeps getting cut?

Your work is the first thing dropped when time runs short, and you are tired of explaining why it matters. Having to justify your existence over and over is its own kind of exhaustion. It is fair to be worn down by it. The trouble is that good research prevents problems, and prevented problems are invisible. No one thanks you for the disaster that never happened. So instead of defending research in the abstract, tie it to what people already fear losing. Show the cost of the mistake you helped them avoid. Speak their language, not yours. You will not win everyone, and you don't need to. Find the few who understand the value and build with them. Pick one recent case where your work changed a decision, and keep it ready. When the doubt or the budget cuts come, you will have something solid to stand on instead of starting from nothing.