A common failure we are seeing in the separation of powers doctrine, especially in political systems with formal branches for executive and legislative (not dumped together in the House/Assembly like they are in parliamentary systems) is the state of exception where the legislative sidesteps their responsibility and allows the executive to rule by decree. This is happening in Venezuela with ley habilitante.

From the first article:

The National Assembly has given initial approval to a measure that would let President Hugo Chavez enact laws by decree for 1 1/2 years, a key step in what the leftist leader calls an accelerating march toward socialism.

The law is expected to easily win final approval next week in a second session of the legislature, which is filled entirely with Chavez allies.

Two things from this, one: parties can actively undermine liberal democracy and establish state's of exception. This occurred in the United States and even in Australia which has poor separation of powers anyway. A quick path to tyranny is party homogeneity in both the legislative and executive.

Two: the state of exception is the exact opposite to liberal democracy. The latter is impossible while a state of exception exists, and with Chavez getting an 18 month rule by decree he is effectively a permanent dictator. Venezuela is in trouble - already many of his economic plans suggest that Venezuela will be in for a rough ride in more ways than one.

Carl Schmitt wrote that without a friend-enemy relationship there was no political. This is a step up from the Hobbesian all against all, to many against few. Schmitt's argument was that the pluralism in liberalism, and its rejection of violence through absorption of liberty and moral consciousness, leaves the political bereft of meaning, so an 'other' has to be created to make the political - political.

There is an 'other' to liberalism and republicanism. It is the state of exception. Unitary government under the whim of the executive is tyranny. A state of exception, or state of emergency, or law by decree, or signing orders, or ley habilitante - whatever - they are all examples of tyranny and despotism within the appearance of separation of powers, constitutionalism and republicanism.

When the executive gets control of the legislative, and usually this is through the party machinery, arbitrary government becomes embedded in legislation. This bill in Venezuela to enable law by decree is an example. Australia has similar legislative issues, for instance the migration act amendment contains the language, "Minister to exercise power personally" which is governance by decree.

In a state of exception: liberal democracy, republicanism and individual moral consciousness cannot exist. In other words liberty is at the whim of tyranny. If western institutions are having a tough time dealing with the executive governing by emergency, then I suspect Venezuela will be in for an even rougher ride.