The Doctrine of Resistance

Now, I'm not afraid to admit that I am quite the amateur when it comes to understanding this topic; I am neither a noodle-spined pacifist, nor a hardcore theonomist. Rom. 13 obviously has much to say in the way of respecting and honoring leaders whom God has appointed. Likewise, God also requires disobedience to rulers in certain situations (e.g. Daniel and his buddies refusing to bend the knee to King Nebuchadnezzar). All this to say, I came upon an interesting quote by John Knox, the great Scottish Reformer:

"If their princes exceed their bounds, Madam, no doubt they may be resisted, even by power. For there is neither greater honor, nor greater obedience, to be given to kings or princes, than God hath commanded to be given unto father and mother. But the father may be stricken with a frenzy, in which he would slay his children. If the children arise, join themselves together, apprehend the father, take the sword from him, bind his hands, and keep him in prison till his frenzy be overpast 4 think ye, Madam, that the children do any wrong? It is even so, Madam, with princes that would murder the children of God that are subjects unto them. Their blind zeal is nothing but a very mad frenzy, and therefore, to take the sword from them, to bind their hands, and to east them into prison, till they be brought to a more sober mind, is no disobedience against princes, but just obedience, because it agreeth with the will of God" (http://www.reformed.org/master/index.html?mainframe=/documents/knox/knox_to_mary/knox_to_mary.html).

The basic question arises: what separates subjection and rebellion? In the case of Knox's illustration, it is the "dutiful" son that binds his father when his father goes mad, and the non-dutiful son that blindly obeys, that being the death of him (and surely others). Furthermore, might some see this son as rebelling against his father? This sounds silly, but why? Would this son not be in strict disobedience to his father were he deny his father's request of his son's blood?

This running illustration gained some traction in my mind due to the recent Obamacare bill. This bill will most likely result in tax-funded abortions. The dots seem to connect quite nicely with Knox's illustration; but is the answer simply to refuse to pay taxes to the government? My initial answer is yes. I don't want to give my "father" the means to satisfy his thirst for innocent blood. But my out-of-context- Romans 13 side says, that no matter to what extent my rulers shake their fists at Almighty God, I am bound to give to them whatever they request of me.

The short answer: I don't know. I'm not sure how Christians should respond should that evil day come when our labor funds murder. Some men say pay up; others say think twice.

Thoughts?