Erik Moberg ã:
A Theory of Democratic Politics
23.1 Ė SOME CONDITIONS FOR THE SYSTEMíS PROPER FUNCTIONING
Since the main actors in the legislature are likely to be individual main actors the threats to the systemís functioning, in the form of clashes between the legislature and the president, that is blocking and obstructive behavior in the legislature, are much smaller here than in the presidential, proportional setting.
Still some such threats may exist. If so, the likely reason is that the legislators for some reason are dependent on political parties, and that the party leaderships somehow manage to discipline their troops. A corrective may be the introduction of primaries, and perhaps also of referendums and initiatives.