I am not a big fan of the "must get 50% of the vote to avoid a runoff" electoral system in Presidential Democracies.
Consider the current case of Colombia:
Santos got 46.5% and his nearest challenger, Mockus, got around 21.5%.
Where I come from, people, that's an ass-whoopin'.
There's no need for the time and expense of another round of voting.
Couldn't you make the runoff conditional?
Like if one candidate gets 40% or more and more than twice as many votes as the second place finisher, then no second round will be held?
Shouldn't Mockus just back down now and accept that, in the words of Mo Udall, "the voters have spoken, those bastards!"
Whats wrong with just letting the highest vote getter win, regardless of their absolute percentage, like the USA and Mexico?