While some Libertarians are against compulsion on principle, I know of no one really that would argue against the idea that education isn't necessary for republican forms of government in principle. Education provides the means of the individual to prevent tyranny, to understand avarice as a corrupting influence in politicians, and it's opposite, virtue, that an uneducated man is both not fully formed unless educated, and it's a duty and obligation of the state and the individual to pursue enlightenment.
Consider the works of Thomas Jefferson (Note that Jefferson doesn't constrain education to politics alone but also to virtue, history and science, although he sometimes uses that term for learning in general):
"I know no safe depositary of the ultimate powers of the society but the people themselves; and if we think them not enlightened enough to exercise their control with a wholesome discretion, the remedy is not to take it from them, but to inform their discretion by education. This is the true corrective of abuses of constitutional power." --Thomas Jefferson to William C. Jarvis, 1820. ME 15:278
"Every government degenerates when trusted to the rulers of the people alone. The people themselves, therefore, are its only safe depositories. And to render even them safe, their minds must be improved to a certain degree." --Thomas Jefferson: Notes on Virginia Q.XIV, 1782. ME 2:207
"The most effectual means of preventing [the perversion of power into tyranny are] to illuminate, as far as practicable, the minds of the people at large, and more especially to give them knowledge of those facts which history exhibits, that possessed thereby of the experience of other ages and countries, they may be enabled to know ambition under all its shapes, and prompt to exert their natural powers to defeat its purposes." --Thomas Jefferson: Diffusion of Knowledge Bill, 1779. FE 2:221, Papers 2:526
"The information of the people at large can alone make them the safe as they are the sole depositary of our political and religious freedom." --Thomas Jefferson to William Duane, 1810. ME 12:417
"Though [the people] may acquiesce, they cannot approve what they do not understand." --Thomas Jefferson: Opinion on Apportionment Bill, 1792. ME 3:211
"If a nation expects to be ignorant and free in a state of civilization, it expects what never was and never will be." --Thomas Jefferson to Charles Yancey, 1816. ME 14:384
"Convinced that the people are the only safe depositories of their own liberty, and that they are not safe unless enlightened to a certain degree, I have looked on our present state of liberty as a short-lived possession unless the mass of the people could be informed to a certain degree." --Thomas Jefferson to Littleton Waller Tazewell, 1805.
"Freedom [is] the first-born daughter of science." --Thomas Jefferson to Francois D'Ivernois, 1795. ME 9:297
"Above all things I hope the education of the common people will be attended to, convinced that on their good sense we may rely with the most security for the preservation of a due degree of liberty." --Thomas Jefferson to James Madison, 1787. Madison Version FE 4:480