A couple of years ago Brian Micklethwait posted on this subject here in Samizdata.

“If all they did at elections was announce the winner, like on Oscar night, this “wasted vote” argument might have some force. But as it is, every vote is not only counted, but every total is announced, and scrutinised, and analysed. Any detectable surges of opinion are most definitely taken into account, even if only by the Big Parties concocting some different lies to replace their old ones.”

Another parallel: although not all people describing themselves as Scottish and Welsh Nationalists want the dissolution of the UK, but some do, and some of those have seats at Westminster. I suppose the idea is that if they gain most of the seats for Scotland/Wales they will have moral authority to secede.