The Conservative has won both most seats in parliament and share of votes (see figure below). However it does not actually “win” this election, as we all know that it has no absolute majority (326 seats) in the parliament.
So why there is a rule like this (no majority=no win)? One big reason is that the party without overall majority has no absolute control over other parties; other parties could come together to reject the bills proposed. Here I am also going to show that, technically the party with most seats/votes but without majority has nowhere to claim to be “winner” or voters’ ultimate choice. On the hand, parties ranked 2nd or even 3rd may actually be the choice of voters.
Let’s looked at the 2012 Summer Olympics host city election results:
|City||Round 1||Round 2||Round 3||Round 4|
|New York City||19||16||–||–|
It is interesting to notice that London was not always ranked 1st in all rounds of votes, though London won eventually. In round 2, Madrid actually had the most votes, however in round 3 it received the least votes. It is clear that those who voted New York City (NYC) previously in round 2 turned to vote either London or Paris in round 3. This clearly shows that the voters did not actually think Madrid was better than either London or Paris, though Madrid had most votes in round 2. Assuming the voters’ opinion was consistent in all rounds, the only reason that Madrid>London in round 2 is because votes were spread among other cities, and particularly some votes were “wasted” on NYC. Whichever the way, it is clear that the voters was in no way to think that Madrid was better than London, which is confirmed by the following round of votes.
Now following the same logic, despite the Conservative won the most seats, it does not won overall majority (50%), and thus one cannot claim that the British voters genuinely believed that Conservative is better than Labour or Liberal Democrat. It may as well that Labour was actually the ultimate choice among the voters, and thus the true winner.
The only way find out who is the true “winner” is to vote in several rounds, like they did in Olympic host city selection. I know, that is too costly (i.e. impractical) for a general election; and I don’t see how it fits the current political system. After all, we have to keep in mind that democracy is not perfect and sometimes just doesn’t work (remember Adolf Hitler?).
PS. This reminds me the classical red bus/blue bus choice modelling problem. Suppose there are two modes people can choose: car and blue bus; and each mode has 50% of road users’ preference. Now image the following situation that half of the blue bus are pained in red colour. Then the road users’ preference for each mode would be 50% for car, 25% for blue bus and 25% for red bus. Now the question is, based on this "statistics”, do people really think that car is a far better transport mode than red bus? (we only changed the colour of the bus!)