The second figure is closer to the truth. The establishment parties do NOT represent the overwhelming majority of American's interests, and overlap each other far more than they admit. Moreover, the "grassroots" common people are a far greater number, and together represent a potentially greater force. While each of these has an "extreme fringe", they actually have a great deal in common - a new center. This new center should NOT be confused with the corporatist "centrist" compromise crafted by the mainstream parties. The establishment elites do NOT want this common ground to form, and actually act to whip their OWN fringes to voice extreme positions that drive these populist sentiments apart, and poison the chances of discovering this common ground. The "true divide" is not between the left and the right, but between the "Big People" career politicians and corporate cronies above, and the "little people" below who actually pay taxes and still struggle to make ends meet.
Do not be taken in by the overheated rhetoric of talk show hosts whose goals are merely to garner ratings or act as shills for establishment positions. There has never been a better time for us to discover and settle this common ground.