Answer:
Tweedle- dee fears a threat of retaliation from Tweedle- dum.
Step-by-step explanation:
This protectionism argument centers on the fact that one party will try to affect the other if it feels that this first party affected them in the first place.
Retaliation means carrying a harmful act towards another in response to them carrying out a harmful act towards you.
In this example we can see that Tweedle- dee decides to maintain his trade barriers high, in order to avoid what he believes to be retaliation on Tweedle- dum's behalf.