Everybody knows that Democrats and Republicans are barely speaking these days. But two political scientists at the University of California at San Diego are statistically quantifying this mutual contempt: “Political polarization is at a post–Civil War high,” says Keith Poole, poly sci prof who, along with two academics at other institutions, has carefully plotted the partisanship in Congressional roll call votes from the 1870s to the present. Today’s yawning and widening gap between Republicans and Democrats (both Northern and Southern) is startling.

In the adjoining office at UCSD is Gary Jacobson, another poly sci prof. Jacobson plots the polarization of the public, as well as partisans and activists within the public, based on opinion polls. The citizenry is not as starkly divided as the politicians are, but issue-oriented partisan groups despise one another with unprecedented intensity.

Rhetoric is heated. Parents pull their children out of school so they won’t have to hear the president give a speech. Jacobson cites health-care reform. “Democrats favor it and Republicans oppose it without even knowing anything about it,” he says. Opponents spread tales of death committees and free health care for illegal aliens even though such measures are not in the package pushed by President Obama. “The audience for wackiness is larger than it used to be,” says Jacobson. “A larger proportion of people are willing to believe unlikely things because of partisan biases.”

Poole takes a different view of the health-care debate: “The Democrats and the president say we can pass health-care reform, and ‘Happy days are here again.’ But it isn’t true. They can pass it but can’t control costs. We are going to go bankrupt at this rate.” Poole would like to see some kind of a compromise, but polarization blocks the possibility. “We have to rein in the cost of entitlements [primarily Social Security, Medicare, and Medicaid],” he says, but “the two political parties are so polarized that they are incapable of coming up with bipartisan deals” to make such reforms.

“Whatever health-care bill emerges will be Democratic — a center/left coalition,” says Jacobson. “The Republicans have no center; they have just a right.” However, he concedes that some Republicans will oppose it on economic grounds, not simply on party strategic grounds.

Poole points out that in the past, important pieces of legislation zipped through Congress with wide backing. “Social Security passed with a bipartisan majority in 1935,” he says. “Medicare passed in 1965 with the support of 50 percent of Republicans in both houses [of Congress].” And in the early 1980s, a bipartisan coalition made changes that stabilized Social Security’s finances for several more decades.

The book that Poole coauthored, Polarized America: The Dance of Ideology and Unequal Riches, came out in 2006. The split between the two parties has widened since then, says Poole.

Similarly, Jacobson’s book, A Divider, Not a Uniter: George W. Bush and the American People, came out in 2006 and is now being revised to cover the period through 2008. The theme of the book, backed up by polling data, is that although Bush promised to be a uniter, his presidency deepened and widened the ideological split between the parties to an alarming degree. Indeed, polls show that Bush was the most polarizing president since statisticians began testing Americans’ opinions 50 years ago. The most factional issue between Democrats and Republicans continues to be the Iraq War, says Jacobson. Opinion on the Vietnam War “was polarized, but not on party lines,” says Jacobson. (President Lyndon Johnson was a Democrat, but it was liberal Democrats who protested the war most vehemently.)

Poole and Jacobson cite a great irony: although the parties are deeply divided, they are both in the pockets of Wall Street and the business community. You would think it would be warm and snug in those pockets, but it apparently isn’t. Decades ago, Democrats got their funds from labor and Republicans from business and Wall Street. But labor has shrunk and lost its political puissance. “Democrats are much more reliant on business and corporate money than they once were. Democrats are getting plenty of support from Wall Street,” says Jacobson.

Agrees Poole, “Wall Street basically owns the two major parties. It gives so much money, there is not likely to be much reform [of the banking industry] coming forward.” He cites the problem of moral hazard: “Not letting the big banks fail is setting us up for another problem. It is a terrible mess.” But the polarization — and both parties’ sticky fingers — will prevent any solution. “They hate one another, but they are both getting massive amounts of money from huge economic interests. It is a total mess — really depressing. As long as they fly under the radar, the elites control. But if the public gets mad, the Congress does what the people want. What these characters in Congress care about the most is getting reelected.” But the public isn’t aroused enough to rebel, largely because the financial matters are so complex that few understand them.

Poole and his two collaborators have shown that, beginning in 1979, political polarization and income polarization rose in tandem. As a larger and larger share of wealth and income went to the fattest cats, political partisanship also grew. Although many of the superrich gave to both political parties (that’s why each party is in business’s pockets), many billionaires gave more heavily to Republicans. Tax cuts for the rich and increasing economic conservatism may have been factors.

By 2007, the richest 1 percent corralled a startling 23.5 percent of national income, highest since 1928, according to data from economists Emmanuel Saez of the University of California at Berkeley and Thomas Piketty of the Paris School of Economics. During the period, political partisanship also widened, says Poole. Piketty and Saez expect that income percentage to drop to between 15 percent and 19 next year. That’s mainly because the superrich are heavily into financial assets, which have lost value dramatically.

If the superrich’s percentage of income declines steeply, will political polarity also decline? Poole doesn’t think so. The political partisanship “is still tied to economic inequality,” he says. “It’s true that the upper end has taken a hit, but the lower end has taken a worse hit, and it will be years and years before we come out of the economic downturn.” Piketty and Saez think the superrich’s percentage of national income is likely to bounce back up once the economy turns up.

Sums up Poole, “The Republicans ran the country into the ditch, and now the Democrats are having their turn running the country into the ditch.” And they enjoy each other’s misery.