Opposition, Party of 2

It seems to me that the main problem with political parties is that they are run by politicians, which gives me an idea for a new party tentatively named the Opposition Party [1][2]. The rules would be something like:

A. No member could run for office: No candidates, no majority or minority power, no chance of being corrupted by being in charge.
B. The party would be vocal contrarians of whoever has political power.
C. The party would endorse politicians from other parties, but it would only endorse incumbents in the most extreme situations.

It wouldn't work of course, but that's okay. It's not as if the current parties are working, either.

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[1] OPP for short?
[2] I am thinking specifically of the US, but perhaps it would work in other democracies as well.