Small compromises teach larger ones how to enter.

Small compromises rarely stay small, not because of a slippery slope but because of precedent. Once you have crossed a line for a good reason, the line has moved, and the next crossing needs a slightly weaker reason. Each one makes the following one look reasonable by comparison.

Pay attention to the first small compromise rather than the large one. That is where the decision is actually made, and it is the only one you can still make cheaply.