Just as legislation passed with bipartisan support is seen as morally commendable regardless of its content, politicians who frequently cross party lines are deemed similarly virtuous regardless of their reasons for doing so. You would think Gergen was a social and political leper rather than a prestigious, highly paid member of the Washington elite. According to the ethic of bipartisanship, politicians are tugged between the polar forces of their own self-interest, which means upholding party loyalty, and the public good, which means the opposite. To be sure, abandoning party discipline has costs. But it also has benefits.
Moderation is a way for members from swing districts to avoid controversy with their constituents.
Senator Joe Lieberman's bipartisanship is a function not only of his temperament and moralism but also of his alliance with Connecticut's insurance, gun, and submarine industries, which urge him to take positions more favorable to business and the military than those of most of his Democratic colleagues. If Representative Connie Morella, a Republican in a liberal Maryland district, didn't frequently challenge the GOP leadership, she'd be out of a job. Conversely, often the toughest thing for a congressman to do is to buck his own constituents and back his party's leadership. In 1994, many Democrats lost seats for supporting President Clinton's tax increase. James Rogan, a conservative Republican in a moderate district, voted with his party for impeachment in 1999, contributing to his defeat the next year.