First-past-the-post voting is a ghastly system, but it has one advantage: it's easy to understand. There's a field of runners, the starting gun fires, and the winner is the one who collects most votes.
The Single Transferable Vote system that we'll be using in this election is fairer, but poses questions that can sometimes be hard to answer.
That's because this election, we're told, is about unionist vs unionist, nationalist vs nationalist. The UUP feels Mr Paisley's breath on its neck and doesn't like it. Sinn Féin moved past the SDLP at the Westminster election and looks set to increase its lead this time around.
So let's imagine it's November 26 and you're a nationalist and you've just entered the voting booth. The first bit is easy – you've given your first preference vote to your chosen party, the SDLP or Sinn Féin. Now what?
In the past, Sinn Féin voters have tended to give the SDLP their second preferences; SDLP voters have been a bit slower to return the compliment. In fact, in the 1980s and early 1990s, Sinn Féin could have expected little more than a quarter of transfers from the SDLP. Since the Good Friday Agreement there's been a noticeable shift.
In the 2001 local elections, some 65% of second preferences from the SDLP are said to have come Sinn Féin's way. Why? Probably because SDLP voters, who had been reluctant to give second preferences to a party they saw as linked to violence, decided that those days were gone. Sinn Féin second preference votes rose dramatically.
The expectation is that the same will happen again in this election, only more so. Which is nice for Sinn Féin, but at the same time sort of surprising.
Let's go back to that polling booth on November 26. You're an SDLP supporter and you know that your party is in a serious, life-threatening struggle with Sinn Féin. So what kind of sense does it make to give second preferences to a party that may be going to overwhelm yours?
And if you're a Sinn Féin voter, what sense does it make to give a leg up to the very people you want to replace – the SDLP? No way, says the SDLP voter. No way, says the Sinn Féin voter.
Only then they check and see that the alternative is to give their vote to a unionist candidate. Yes, they come in 57 flavours and under 57 banners, but they're still all unionist. No way, says the SDLP voter. No way, says the Sinn Féin voter.
But hold on a minute. Maybe John Hume was right: maybe this is a post-nationalist era. Certainly nationalist and republican strategy has been to make an unequivocal commitment to the Good Friday Agreement, so the more pro-agreement unionists get elected, the more likely that strategy is to bear fruit. So of course nationalists and republicans should be doing all they can to help pro-agreement unionists get elected.
Certainly Martin McGuinness thinks so. On Monday of this week, an English newspaper reported him as "urging republicans to give transfer votes to unionist politicians who support the Good Friday Agreement, in an effort to boost the Northern Irish peace process".
Reading it, SDLP supporters might have felt tempted to agree with Mr McGuinness – especially if they went on to read the second part of that report. Because in it, Mr McGuinness expressed confidence that his party can "overtake the SDLP as the biggest nationalist party in the power-sharing Stormont".
Our SDLP person-in-the-voting-booth might decide that love and fear – love of the agreement, fear of republican success – are two good reasons for giving second-preference to a unionist before a republican. And our Sinn Féin person-in-the-booth might decide Martin knows what he's talking about and by-pass the SDLP for a pro-Trimble UUP candidate.
Seen that way, it's tempting to believe this election could witness a historic electoral shift in nationalist thinking. Not an abandonment of traditional party loyalty, but an electoral reaching-out to unionism.
Tempting, but it won't happen. Call it short-sighted, call it sectarian, but most nationalist voters will simply not give their second preferences to unionists if a fellow-nationalist is on the ticket. Even if that fellow-nationalist is a political enemy. And the reason they won't is not because they're short-sighted or sectarian, it's because they smell change. Nationalists sense that profound political change is on the way on this island, and in their guts they believe that supporting nationalist candidates all the way down the ticket will hasten that change. Only when that's done will they consider saving Dave.
