head someone or something off at the pass
head (someone or something) off at the pass
1. Literally, to prevent someone or something from reaching or passing a certain point, especially to escape. If we take this route, we should be able to head them off at the pass, sheriff! Janet's going to spill the beans about our plan to the teacher. I think she's going through the library, so if we're quick, we can head her off at the pass.
2. By extension, to preempt or forestall someone from doing something or something from happening. The aim of this new treatment method is to identify the disease much earlier and then head it off the pass, rather than simply managing the symptoms it presents down the line.
head (or cut) someone or something off at the passforestall someone or something, especially at a critical moment or at the last possible moment.
Pass is used here in the sense of a narrow route through mountains.