Modern political science tends to consider the contrast between democracy and republicanism as the contrast between direct democracy, where the citizenry is the legislature, and representative democracy, where the citizenry elects the legislature*. Since direct democracy seems at best unwieldy and at worst practically impossible, republicanism is held up as the only viable alternative. But there's another contrast possible, the contrast between the existing trustee model of representation and the delegate model.
*In a parliamentary system, the legislature (usually the majority party in the legislature) elects the executive; in most presidential and semi-presidential systems, the the citizens elect the president directly. The sine qua non of republicanism, therefore, is the election of the legislature.
In the existing trustee model, we elect individuals we trust to make the right decisions, even if those decisions are temporarily unpopular. Because we explicitly privilege representatives to make temporarily unpopular decisions, we must explicitly protect them from the consequences of unpopularity. Thus we elect representatives for fixed terms, and evaluate the totality of their performance at the end of their term. We also allow them to operate secretly or covertly. If we trust someone (and if we have no way of immediately overturning their decisions), it's more efficient to let them make decisions in secret, or make decisions we can discover only after substantial effort.
The trustee model is discussed at some length in the Federalist Papers. One justification for the trustee model was the protection of minorities: a trustee representative, because of his superior wisdom and the necessity of taking a somewhat longer view (at least to the next election) would, the Founders proposed, make "oppression" of the minority by the majority more difficult. Another consideration, perhaps more important, was that a trustee model would protect the position of the capitalist ruling class. (The code phrase, which appears both in the Federalist Papers as well as the Constitution), is a prohibition on the forgiveness of debts.) The trustee model was quickly abandoned as way of protecting against the "tyranny of the majority"; the inclusion of the Bill of Rights places this task firmly in the hands of the judiciary. In reality, the trustee model only protects the ruling class.
But using the trustee model brings up a more fundamental question: why involve the people (at least those people outside the ruling class) at all? If you're going to protect the ruling class, why not do so directly? A simple argument is just that the Founders believed that trustee representation would more efficiently legitimatize the new government. The colonies had, after all, been electing their legislatures for a century. But there's a deeper argument: the capitalist ruling class of the late 18th century did not trust the people, but they also did not trust each other. As much as they wanted to protect capitalism from the people, they wanted to protect capitalism from other capitalists. They did not want the (presently) richest capitalists to unconditionally acquire state power, and set themselves up as a politically, rather than economically, privileged elite. They did not want capitalism to degenerate into de facto monarchism. There was no internal way to avoid this degeneration, so they pushed the resolution of disputes within the capitalist ruling class to (some of) the people.
Lenin, whom I believe was at heart a democrat, favoring a democratic political process, made the fundamental error of not immediately making the legitimacy of members of the Communist Party of the Soviet Union, even as trustees, formally dependent on a democratic process. It is up to historians to determine whether or not his error was excusable or inevitable: he inherited a country compromised by imperialist exploitation, ruined by the First Imperialist War, he had to fight a savage civil war, and had nothing even approaching democratic popular traditions; it is entirely possible that a democratic process would have immediately doomed Russia. I don't think Mao Zedong was at heart a democrat, but the historical, material circumstances were perhaps even more dire in 1949 China than in 1917 Russia; if a democratic process really was untenable, we can fault Mao only for his lack of pious hypocrisy. But, regardless of the inevitability or exusablity of their errors, they did err, and we are not obliged to sanctify or repeat their errors.
It's not terribly difficult to correct the error without reproducing the class privilege inherent in the trustee model: the delegate model of representation.
In the delegate model, where possible, we handle matters of state power by direct democracy. Direct democracy works reasonably well for small groups of people, and we are "naturally" made up of small groups: e.g. neighborhoods, small businesses, interest groups. We can, for many matters, place some state power directly in the hands of the people themselves, and (with some limits) let the majority of the small group directly "rule" the group. This process has the twin advantages of being as "purely" democratic as possible; more importantly it habituates people to the techniques, skills, and special problems of exercising state power.
Where we cannot efficiently implement direct democracy, we resort to delegates. A delegate differs from a trustee in that a delegate's constituency does not trust a delegate to act in their interests. Instead, the constituency continuously evaluates their delegate, and ensures that she acts in accordance with their interests. Unlike a trustee, the delegate serves at the pleasure of her constituency, and therefore the constituency may recall and replace her at will. Second, a delegate must act absolutely transparently; the constituency must know, or be able to easily discover, exactly what she is doing at all times. Finally, the delegate must be absolutely free of conflicts of both personal and third-party interests: she must be beholden only to her constituency; her personal interests should be serving the will of her constituency.
The delegate model of democracy does not solve all political problems. Like any other democratic system, including republicanism, a theory of government that includes a delegate model must generally confront the philosophical and theoretical limitations of majoritarianism. The delegate model still leaves the issue of "tyranny of the majority" unsolved. But neither does the the existing republican model solve the problem; in almost all republics, maintaining the proper rights of the minority is a function of the judiciary. Because it does depend on the people, the delegate model shares the problems inherent to any democratic or semi-democratic system.
Perhaps more critically, the delegate model is by design not as stable as the republican model. We can count on a republican government having the same people in it for the shortest term of office (e.g. two years in the United States); in contrast a delegate government can change arbitrarily. As noted, the delegate model intentionally undermines legislative stability to prevent a minority class from monopolizing state power. An overall model of government that includes delegation must, however, directly address the issue of stability.
A governmental system is complex; it consists of many institutions. Indeed a government that consists of a single institution (such as communism of the parties, which had a single governing institution, the national Communist Party) has a single point of failure, which we engineers consider a Bad Thing. In a complex system, if one institution fails, the other institutions can mitigate the effects; they can also exert pressure to correct the failing institution. The delegate model of democracy specifies only one institution. I will be exploring other institutions of democratic communism in further posts.