Benjamin Constant contrasts what the ancient Greeks and Romans understood by "liberty" (libertas) and what liberty meant in the age of classical liberalism. He demonstrates that true liberty is not two wolves' freedom to vote a lamb into their jaws, as most modern politicians and so-called political scientists would have us believe. The ancients failed to understand that political liberty is a means to an end, not an end in itself. It is a safeguard for individual freedom. Without individual liberty, political liberty leads to the worst kind of despotism. By closely imitating ancient republicanism, the French revolutionaries ushered in a tyranny far more oppressive than that of Louis XVI or even his more absolutist predecessors. The Reign of Terror, in turn, paved the way for three modern atrocities that seek to partially reconstruct this ancient idea of "collective" liberty (an oxymoron and a misnomer) - democracy, nationalism and socialism.
Moreover, while ancient republicanism revolved around war as society's chief concern and source of virtue, modern liberty is based on a more rational and sound way of obtaining wealth - commerce. Modern capitalism is inherently anti-war (that is, aggressors should be punished but a free society cannot be an aggressor itself because it has much more to gain from peaceful trade than from military plunder). Below is a quote:
Thus among the ancients the individual, almost always sovereign in public affairs, was a slave in all his private relations. As a citizen, he decided on peace and war; as a private individual, he was constrained, watched and repressed in all his movements; as a member of the collective body, he interrogated, dismissed, condemned, beggared, exiled, or sentenced to death his magistrates and superiors; as a subject of the collective body he could himself be deprived of his status, stripped of his privileges, banished, put to death, by the discretionary will of the whole to which he belonged. Among the moderns, on the contrary, the individual, independent in his private life, is, even in the freest of states, sovereign only in appearance. His sovereignty is restricted and almost always suspended. If, at fixed and rare intervals, in which he is again surrounded by precautions and obstacles, he exercises this sovereignty, it is always only to renounce it.