In strictly
technical terms this means 50 percent plus one of the electorate's ( which usually means
Congress)
vote. I tend to think of it in the same way as a
controlling
partnership in a
business with the 51 percent controlling the 49 percent.
The actual application of it is something more like projecting the wants of the majority of the voters. The perception of what the public wants then becomes the actual legislative voice of the people. This becomes especially prominent around election time and especially scary when you consider just how much time and money is put into lobbying.