Let's look at Adam's poll: 79 percent support the compromise. Totally too small of a samples size, but just for shits and giggles, let's assume that is representative. 75% is NOT consensus, but 79% is?
Consensus is 100%
If you mine a block that 79% agree with you create 2 forks. One with 100% consensus on the old rules, and the other with 100% consensus on the new rules.
Unless you can force the 21% that disagree with the new rules to accept the change and abandon their block history, you effectively now have 2 separate bitcoins.
http://qntra.net/2015/01/the-hard-fork-missile-crisis/ <~ I thought everyone knew this by now?