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Mandatory voting can have one big flaw

A voter wears an, 'I Voted', sticker after casting her ballot at The Coliseum where a polling station is setup on November 4, 2014 in St Petersburg, Florida.
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A voter wears an, 'I Voted', sticker after casting her ballot at The Coliseum where a polling station is setup on November 4, 2014 in St Petersburg, Florida.

Ever heard of "donkey voting?" I don't mean voting Democrat, I mean casting your ballot in the order in which the candidates are listed, usually because you don't care who wins, you probably don't even know who's running, and you just want to get out of the voting booth and down to the pub for a cold Foster's.

As the President of the United States holds up Australia as the model for a compulsory vote, it's worth noting that donkey voting is particularly apparent under what he calls this "transformative" system. You can understand the President's argument in theory. After all, approximately $2.6 billion spent on the 2012 election with a measly 57.5% voter turnout doesn't seem like a great ROI.

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And it's true that when faced with a fine of up to $170 plus court costs and a possible criminal conviction if you don't vote in Australia, you may take more notice of the political debate and make the effort to make your voice count… or you may not.

So in the meantime, if compulsory voting is indeed headed this way, and if you're a candidate, make you sure you get your name at the top, because the donkey always favors he or she who is listed first!

Commentary by Mandy Drury, co-host of CNBC's "Power Lunch." Follow her on Twitter @MandyCNBC.