This is a rhetorical tour de force, attention grabbing, intriguing, and offering a fresh perspective. I don’t agree with the conclusions, but appreciate the piece!
The connection between politics and romance-leading-to-marriage is the problem of reconciling conflicting agenda. It is actually easier with marriage because here you only have two agendas to reconcile unless you’re dealing with schizophrenia, multiple personalities, manic/depressive, and/or in-laws, kids, and incompatible religions. But I digress.
You begin by drawing the parallel between the parties in marriage and the parties in national government. Overcoming (transcending) self-interest and working to identify the common good is the challenge which is too often failed by the inability of one or both parties to recognize a common interest. An additional question is accurately identifying what is in the interest of either the self, or the common. A bigger house with bigger payments may or may not be in the common interest. Giving junior a room of his own with a tv may not be in his best interest in that supervision is what junior may need, even if his younger sister may not.
Was another massive social welfare program -Obamacare- in the common interest? Enabling more people to buy limited resources like medical care and college will cause the prices to go up because we increased demand without increasing supply. Theoretically, the supply will go up in response to the continued demand, and so we have our Corinthian and ITT colleges to remind us that quality college programs are a limited commodity. The collapsing insurance market may be such a reminder that market forces cannot be ignored even if our altruistic motives are pure. (Love does NOT conquer all- ask anyone who stayed married.)
Your point about fictive identities is well taken and deserves to be developed further. The rise of nationalism in many quarters raises questions as to loyalty and which are ethical and mandatory versus which are merely preferred. For example, Gandhi led a national movement in the name of justice which many westerners applauded, but to his shock, gave rise to the nationalistic movement among the majority Muslim provinces which chose to break away from India even as India brook away from Britain. Just as marriage requires a new identity for the couple, so national union requires a common identity, and this we see fought out in our politics.