Ayn Rand actually answered this question herself, though not exactly in this form. "Bipartisanship" is the flip-side of "polarization," about which Ayn Rand wrote an article called "Credibility and Polarization," quoted in the Ayn Rand Lexicon.
(On this topic, see also "A Nation's Unity," which I regard as one of her most brilliant socio-political essays.)
"Polarization" is supposed to replace and obliterate the concept of disagreement on basic principles, but a rational person can't help but wonder: how am I supposed to have truck with someone whose ideas I regard as evil and destructive? "Bipartisanship" is the answer. A claim of evil cannot stand on its own, without some idea of the good — you cannot motivate someone to avoid X, without giving him a Y to pursue in its place. If "polarization" is the ultimate evil to avoid, "bipartisanship" is the ultimate good.
Every anti-concept is also a package-deal: a union of fundamentally disparate units according to a non-essential similarity. "Bipartisanship" links capitulation on principles with legitimate compromise. A "bipartisan" negotiation between a worker who wants a $10-per-hour raise and his boss who wants none, might lead to a $5-per-hour raise. A "bipartisan" negotiation between a woman who doesn't want to be killed and a man who wants to kill her, might lead to the woman's being "only" beaten up. Clearly, these are in fundamentally different categories, yet the concept of "bipartisanship," if applied consistently, would treat them the same.
A proper politician should be willing to work with the other side, wherever possible. But where matters of principle are concerned, "bipartisanship" is a sin, not a virtue.
I answered this question in a recent episode of my Rationally Selfish Webcast. An audio recording of my response is available as a podcast here: NoodleCast #82: Live Rationally Selfish Webcast. The discussion of this question runs from 40:17 to 44:31.
My Answer, In Brief: Given that neither Democrats nor Republicans respect rights, political bipartisanship will likely only spawn some horrible plan to strip us of our rights. For our short-term survival, we need gridlock. For my full answer, listen to the podcast!
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