Vague reference is a common problem in sentences where “this,” “it,” “which” or other such words don’t refer back to any one specific word or phrase, but a whole situation.
Arnold Zwicky calls these things "summatives" ("Why are some summatives labeled 'vague'?", 5/21/2008), and I've been publicly skeptical of blanket prohibitions against their use, since it's often clear in context what the referent is meant to be, and excellent writers from the authors of the King James Bible to Bertrand Russell have been fond of them ("Poor pitiful which", 5/23/2008; "Clarity, choice, and evidence", 5/23/2008).
But a recent political development has led me to re-evaluate my position.
If you were successful, somebody along the line gave you some help. There was a great teacher somewhere in your life. Somebody helped to create this unbelievable American system that we have that allowed you to thrive. Somebody invested in roads and bridges. If you've got a business — that- you didn't build that. Somebody else made that happen. The Internet didn't get invented on its own. Government research created the Internet so that all the companies could make money off the Internet.
The point is, is that when we succeed, we succeed because of our individual initiative, but also because we do things together.
In context, the two instances of that in "… you didn't build that; somebody else made that happen" clearly refer to the "whole situation" evoked by the phrases "Somebody helped to create this unbelievable American system that we have that allowed you to thrive. Somebody invested in roads and bridges." Maybe that great teacher is in there too.
But a very different meaning emerges if you take out of context the sequence
If you've got a business — that- you didn't build that. Somebody else made that happen.
Now it seems as if that refers to the hypothetical business — and instead of an anodyne political cliché about the role of socio-economic infrastructure in enabling business success, you get a bizarre denial of the role of entrepreneurial agency. This opportunity for misinterpretation made the Romney campaign so happy that they posted a clip running the first sentence ("If you've got a business, you didn't build that") over and over, five times:
So a piece of advice to politicians and their speechwriters: Watch those summatives!