Quoting Anders Holmstr??m (anders.sputnik@gmail.com):
The US is modelled on the French system where the executive is formed *outside* the legislature and that is why all votes are essentially "conscience votes".
Correct. Political parties are actually not recognised in the US Federal foundational and operational documents, because, oddly enough, the Founding Fathers were taken by surprise by their rise as an emergent effect of government structure.[1] Anyway, the parties have ultimately no control over a sitting member of Congress (for example), except the indirect influence they have as the source of a certain amount of fundraising helpful for re-election, albeit there are often maverick candidates who dispense with that financial backing and declare themselves a $FOO party candidate irrespective of whether the party's central committee likes or loathes them. (The point is that the party has zero power to decree who may run as a $FOO-affiliated candidate -- for the reason cited below.) Unlike in the Westminster system, neither politicians nor voters have party membership, and neither apply for membership nor pay membership fees, hence also cannot be expelled. Occasional members of Congress decide they don't like the cut of the jib of either of the dominant parties, and declare themselves 'independent'. Currently, ISTR three Senators are such, and choose to caucus with the Democratic Party Senators. [1] E.g., Duverger's Law, http://linuxmafia.com/~rick/lexicon.html#duverger . -- Cheers, "Maybe the law ain’t perfect, but it’s the only Rick Moen one we got, and without it we got nuthin'." rick@linuxmafia.com -- U.S. Deputy Marshal Bass Reeves, circa 1875 McQ! (4x80)