I don't think Neil sacrificed Willie intentionally. His death was an
occupational hazard (however ironic and poignant). Moreover, I don't think
Neil was trying to discredit the Soviets. The KGB were getting rid of their
spy and trying to discredit SIS at the same time -- the "hit" would have
given the Soviets the excuse they needed to quit SALT. Neil was anticipating
a hit (on the negotiator) and using Willie and Mike to protect the Service.
As for how Neil combats communism, well, that was one of the tensions of the
show, wasn't it? I can't recall the episode, but there is a scene between
Neil and C in his car where they talk about this. Neil defends his "dirty
tricks department" because the KGB use dirty tricks. C argues that the KGB
answers to its government. In "It Couldn't Happen Here", Neil says "I
promise I won't kill Stratford-Baker because the system won't let me." To
which C replies, "Then thank God for the system!" Of course, Neil does it
anyway. And so on it goes. Hypocrisy, lies, compromise, contradiction.
Mark