Well, first we should set aside the sense in which "liberalism" names a partisan position in North American electoral and cultural politics. Liberals in this sense tend to embrace liberal government for some issues (drugs, abortion, etc.) while rejecting it for others (minimum wage, environmental regulations, etc.). There is no neat fit between the mode of government and partisan identification, even if there are discernible patterns.
Likewise, I think it is necessary to set aside the sense in which "liberalism" names a theory of state legitimation. In this sense, liberalism asks the question: When is it obligatory that I obey a coercive power? To which liberalism answers: When that coercive power is necessary (and sufficient?) to secure a sphere of equal liberty for myself and my fellows, who are equally obligated thereby to obey. This morality of power and obedience -- basically, the social contract tradition -- has some relationship with liberal government, but is not identical to it. Hobbes offers a liberal legitimation of the state, but not a liberal theory of government. Smith proposes liberal government, but not a liberal legitimation of the state. (Foucault talks about this as the "strategic" difference between "revolutionary" (natural rights, social contract) and "radical" (utilitarian) strands within liberalism. The difference is strategic because the two strands can support one another in various ways, but are not reducible to moments in a dialectical unity.)
Liberalism as a mode of government names the technology of power that governs a natural-social phenomenon by establishing a normal range of incidence and keeping the phenomenon within this range by means of state action on the environmental variables that tend to affect incidence. In other words, liberal government accepts the thing to be governed as an ineliminable (natural) fact of the social world, and, rather than trying to forbid or otherwise abolish it, manages it indirectly by affecting those variables that encourage or discourage it by appealing to individuals' interests. In short, liberal government is economic government, government that understands and respects the economic incentives that produce harmful or unpleasant phenomena, and tries to manage problems by restructuring the incentives.
Now, when things are put in these terms, it seems, in fact, that liberalism is the only governmental game in town. The Right has a moral discourse and an effective political rhetoric, but no independent art of government. The Left has a critical discourse, but neither an effective political rhetoric nor an art of government. Mainstream liberalism has government all locked up -- but has neither a critical nor a moral discourse, and is largely lacking in the political rhetoric department, too! (Hence, the sorry state of the Democrats in the US and the Liberals in Canada, both of which must pin there hopes of electoral success almost entirely on the incompetence of their Rightist competition.)
This is a problem for the Left in that, aside from the momentous problem of, y'know, actually taking power, we have no independent practice of government by which we might wield the power of the state should it somehow fall into our hands. There are, of course, distinctive ends we would like to achieve, but when you ask: How would we go about, e.g., redistributing land, establishing a basic income, etc? the only answers that seem forthcoming are: a) a magical faith in the will of the people (a simple decree, anyone?) and b) ask the economists.
