It is not a question of <consensus of minority parties> but
- an overall consensus system - specifically between "those in power" (forming a majority-coalition) and those in the opposition (forming a minority)
However, the small parties usually form a consensus in favor of the rights and the position of these small parties within the whole system. That is, even if they might disagree on almost anything else.
The mechanisms to make this possible, functional,etc,etc are the mechanisms for first forming parties, then participating in elections, campaigning (public financing according to rules of proportionality,etc), the election itself and finally how decisions are made in the parliament as well as how a governing coalition is formed.
To return to your "consensus of minority parties" one example is that parties can form coalitions in one or many voting districts to "pool" their votes. Note that this is only for that election and that district and also mostly used by small parties, although sometimes between a major party and a small party which has fairly similar goals.
Compare this to a "third party" in USA which in district forms a coalition with thr democrates and in another district with the republicans, although all of this is pretty meaningless in a two-party system for the simple reason that these mechanisms only work when based on proportional representation system (with many parties)
That is, all of the mechanisms I have mentioned are "meaningless" in a two-party system, especially the "strict" two-party system in USA.
However, somewhat meaningful in, for example, UK where there actually are many parties in the parliament, but, on the other hand, a 50% majority is not demanded to form a government (goes to the largest party, eve if they have less than 50% popular support)
In USA the "consensus-mechanisms" are more in the form of having three institutions which must agree, the house, the senate and the president, where normally one institution should "be the other party". (except for over-riding 2/3 majority decisions, ref the 5/6 I mentioned, or except as now, when one party rules in all three)
That is, a system based on and "fostering" so called "adversariality" in contrast to "consensus" |