The Prince: Novel Summary: Chapters 19-20

Chapter 19: Machiavelli elaborates on the necessity of the prince to avoid being hated and despised by his people.  The prince should have two fears: his own people and foreigners.  Yet if he is well respected, well prepared, and well armed, he should have little difficulty in maintaining order both within and without his city.  Above all, a prince who is not hated or despised will be able to guard against conspiracies to overthrow him. 
Besides this, a wise prince must balance the interests of the nobles and the people.  Whenever he needs to "reproach" one or the other, he instructs others to carry out his "dirty work." In this way, the nobles never grow to hate their prince.  In a similar way, he will have to decide between his people and his soldiers.  Having the respect of the soldiers is usually more vital, Machiavelli notes, though many princes have treated their soldiers too nicely.  Above all, the prince should try to satisfy those around him.  This, more than anything else, will make him loved.  Yet each prince will have to evaluate his own situation and work from there.  Though he should strive to emulate his predecessors in part, he must also be able to find political strategies of his own.
Chapter 20: Now Machiavelli discusses the question of whether or not a prince should arm his subjects.  Generally, it's good to arm them, he asserts, especially if they are loyal and trustworthy.  But if the prince chooses not to arm his citizens, they will grow to resent him for not showing them trust.  So Machiavelli resolves that new princes in new states should arm their subjects, but a prince who has just expanded his empire should not give arms to the people in his new territory.  The goal here is to prevent disloyal men from possessing the means to overthrow the prince.  Loyal subjects, on the other hand, can and should be trusted with weapons to protect themselves and therefore their prince.  Sometimes the prince's most combative resisters can become his most ardent supporters if he plays his cards right.
In considering the value of a city fortress, Machiavelli reasons it as such: "The prince who has more to fear from the people than from foreigners ought to build fortresses, but he who has more to fear from foreigners than from his people ought to leave them alone." Thus, the prince's subjects must not hate him or a fortress will do him no good.  It seems all of Machiavelli's assertions stress the value of the prince avoiding the hate of his people.