The Constitution elaborates on these principles, starting with its aspirational Preamble. It requires the consent of the governed be exercised through representative institutions, the essence of a republic (see Federalist 10). It then constrains those institutions with a system of checks and balances (see Federalist 51).
Even as it sets out other powers and responsibilities needed for effective national government, the Constitution makes the exercise of power cumbersome, in order to ensure that it is deliberative. This constitutional scheme itself tends to drive policy to the center. We do not have a parliamentary system in which a party wins a majority of seats and is entitled to govern. In our system, the necessity for compromise springs from our constitutional DNA.
Now, consider the political profile of the country. As the last two elections confirmed, we are a politically centrist people, split pretty much down the middle. The country's political makeup should also counsel bipartisan cooperation.
It's one thing to make a constitutional and political case for bipartisanship and civility. It's quite another to encourage and sustain it. Like all of us, members of Congress respond to ideas and to incentives. The good news is that our founding principles furnish the ideas, and political realities should help with the incentives.
America's leading idea was and is that we're all created equal. To keep faith with that principle, our representatives need to act out of the mutual respect that equality demands. As elected representatives of constituencies of civic equals, they are obliged to treat one another civilly.
Out of this flows an imperative for civility as a matter of political morality. That is, if compromise is a political and constitutional necessity, and if mutual respect is a moral requirement of our founding principles, then developing a politics of civility is essential. This civility stuff is worthy enough in its own right. It makes the business of politics more pleasant. However, it is also the means needed to reach the goal of bipartisan compromise.