[I]n most democracies policies are really written by the executive branch in a collaboration between key cabinet members and civil servants. The legislature’s job is more-or-less to accept or reject these proposals. In America it doesn’t work like that. Even though it’s typical for staff talent to flow from the Hill to the White House and even though the professional staff resources of the executive branch far exceed those of the congress, the details of legislation are written by congress and then it’s left up to the White House to accept or reject the bills.Before going into whether that's a good or bad thing, I should note that this is a bit exaggerated. Yes, Congress can and does write the details of legislation -- but so do the agencies, and so does the White House. It's not unusual at all for the White House to send up draft legislation, or for the White House to actively negotiate even small points of legislative language, or to cut deals with individual Senators or Members of the House. So while Matt is absolutely correct about the difference between the American Congress and most other legislatures in other Democracies, it's really not true that the White House is (or has to be) as passive as he implies. It's not that American democracy has different players than do other democracies -- it's that American democracy has more players. A lot more.
OK, now, time to get to the actual argument. Matt goes through the recent unemployment extension bill and makes the case that Congress is ill-equipped to write legislation; as he puts it: "the congress is simply not well set-up to produce technically sound ways of achieving policy objectives." The case against Congress, which I think Matt would subscribe to, is that they are amateurs who don't have the technical know-how to do the job correctly, and that the politics of Congress makes for all sorts of random results.
So, what are the arguments for the American transformative Congress? There are two types of arguments, in fact; arguments on practical grounds, and arguments on democratic grounds.
First, on practical grounds. The case here is twofold. On the one hand, bureaucracies are subject to all sorts of well-known pathologies, and allowing some amateurs into the process is a good way to check the problems of bureaucracy. On the other hand, while Members of Congress are amateurs when it comes to the technical aspects of policy, they can be experts on one thing: their constituents. Members of Congress have terrific motivation, through the re-election process, to make sure that their constituents are happy with policy, and so may make it their business to know enough that they can avoid harming the voters. Some will also argue that in a very large and very diverse democracy, it's important to inject local preferences into the system, even at a potential cost in overall efficiency.
On theoretical grounds, there's a very strong concern about the dangers that bureaucratic rules poses to democracy, for example in the work of Weber (who calls it an "iron cage") and Arendt, who calls "rule by nobody" and notes the tyrannical form that such a system takes. For them, even the most benevolent bureaucracy is simply not democratic. Of course, a system such as Britain's in which the bureaucracy shares authority with an elected government is not a pure tyranny, but the problem (as seen from this point of view) is that bureaucracies tend to have a lot of advantages within those sorts of systems. The American solution, with separated institutions sharing powers (in Neustadt's words), is a much more effective way to restrict the strength of bureaucracies.
To look at the same question from the other way around, it's just far easier for rank-and-file citizens to affect policy if there are far more elites who are in position to make policy -- and Congress is particularly attuned to hearing the input of rank-and-file citizens. Obviously, these sorts of things have limits; there are a variety of resources that help constituents get the attention of their Members of Congress, and those resources are not equally distributed. But overall, a surprisingly large number of human-scaled groups, and even some individual people, are able to get the attention of Members of Congress to make their case for or against some particular policy. That kind of participation, many would argue (myself included), is democracy, or at least a very important component of healthy democracy -- and it's very difficult without an active, transformative Congress in place.
Congress-bashing is a long and honored American tradition, but it's still misguided. To be sure, there are specific things that Congress does and particular ways that Congress organizes itself that are problematic, but overall there's a solid argument for the practical advantages of the American, Madisonian system, and very strong arguments for the democratic advantages of that system.