I think it's one thing to include it in a party platform in an election campaign—and politicians will always claim they have a mandate to do whatever they have in their platform—but voting behaviour studies and electoral studies continually show that, when people vote, most of the time they are not aware of most of what's in a party's platform. So it's not quite kosher to claim a mandate for everything that's in your platform and proceed in that fashion.
At the same time, consensus is not unanimity, as the Supreme Court has very nicely pointed out on a couple of occasions. I think you can still generate a fairly broad consensus now that we no longer have just a two party system. I think it was very difficult when there were only two parties.