Like most who've commented so far, I'm against compulsory voting too. I believe that those who died for democracy wished for people to have the right to vote, not the compulsory civic duty to vote. I think you should be allowed not to vote, and as such also to accept the consequences of not voting. I personally think it's better to spoil a ballot than abstain though , because you can at least express your disdain with the system in a certain way. Abstaining on the other hand could mean apathy and the fact you're indifferent to the result. Ever since I became eligible I have voted in all my general elections, local elections, the combined-authority mayoral election (relatively new thing that came about only this year I believe) and the EU referendum, all that even despite my dislike for the voting system and the politicians.
