Ribner, Irving. "Political Issues in Julius Caesar."
Journal of English and Germanic Philology 56 (1957):10-22.

Thesis: Ribner begins by rejecting two views: a) that Shakespeare was interested "only in character, and . . . remained aloof from political concerns" (10), and b) that "the play is a vindication of absolute monarchy, represented by Caesar, against the claims of a constitutional system, represented by Brutus" (10). The history of the Roman Republic, says Ribner, was well-known in Shakespeare's time and it was used by many others to teach political lessons, but the political issue in Julius Caesar is not monarchy vs. republicanism; rather it is the danger of tyranny. Thus Caesar is a tragic hero whose flaw is "tragic pride and ambition" (15), and the villain of the play is the savage mob who puts Cinna the Poet to death merely for his name. As for Brutus, he is also a tragic hero, one who is "too much the idealist to cope with the crude realities of politics" (17), and who—more importantly—is doomed by self-betrayal:
The tragic error of Brutus is his entry into the conspiracy, for this involved a divorce between his ideals and his conduct which could lead only to tragedy. For in order to attain an end of public virtue, Brutus commits a private crime: he murders his friend. Shakespeare saw the problems of government in personal human terms. A man must have the public virtues to be an efficient ruler, but he must have the private virtues as well, if he is to be a great and good one. It is ironic that Brutus, so rich in private virtue and so poor in public virtue, should fall because of a single deviation from his personal code of behavior. But when Brutus commits a crime contrary to his own nature and in spite of the promptings of conscience, he is doomed to failure.   (18)
In the end, Ribner writes, Shakespeare took a balanced view:
He saw . . . on the one hand, a lesson in the civil chaos which results when a great and noble leader tries to overthrow long-established institutions and seeks, with support of the mob, to attain a kingship to which he has no lawful claim. On the other hand, he saw the even greater chaos which results when men of noble instincts violate their own natures and enter into evil so that political good may result.  (22)

Bottom Line: Solid analysis