Pew American Values Survey: More Partisan Polarization Spencer Platt / Getty Images Mike Patterson, who is unemployed, eats lunch at Mother Marianne's West Side Soup Kitchen in Utica, N.Y., on May 15, 2012 The headline on Pew's new 25th anniversary American Values survey is probably not surprising to anyone attuned to Washington's frequency the past few years: political polarization has risen sharply, not just in Congress but among voters too. Partisanship now predicts voters" priorities better than factors like race, religion, income and education. That wasn't always the case, and the numbers that accompany this change offer some good explanations for the actions of Democrats and Republicans in government. Policywise, the most important shift since the Pew survey started has been the dramatic reversal of conservative views about the social safety net. In 1987, 62% of Republicans said the government should take care of people who can't take care of themselves; now just 40% say the same - a 35-point difference from Democrats, who haven't changed their views much on the issue. Only 20% of Republicans today say the government should go deeper into debt to help the needy. That shift is reflected in the agenda of congressional Republicans. Paul Ryan has been introducing entitlement-slashing budgets for years; with the base behind him, it's now a pillar of the GOP platform. Given the fair chance that Mitt Romney is elected along with a Republican-controlled Congress, historians may well trace a massive restructuring of the U.S. social safety net back to this change in opinion. The timing of the shift is interesting. Big drops in Republican support for the social safety net have occurred twice: at the beginning of Bill Clinton's and Barack Obama's first terms. It's possible that these voters were reacting to economic forces - it seems reasonable that people would feel the need to retrench in lean times, regardless of the economic merits - but it's hard not to read the falloff as a partisan reaction to a Democratic President. This effect shows up in the broader issue of government efficacy, which Republicans suddenly lose faith in (and which Democrats suddenly believe in) when a Democrat enters the White House. Under Obama, increasing polarization and the lasting effects of the Great Recession seem to have induced what Pew calls the "most extreme partisan reaction to government in the past 25 years." Historical changes in partisan priorities help explain the liberal agenda as well. While Republicans have evolved on fiscal and regulatory issues, Democrats are transforming socially. A decline in religiosity and interest in "old-fashioned values" hints at the issues animating liberals: income inequality (especially between races), gay rights and immigration. That's not to say Democrats don't still favor a social safety net and robust regulation - they do, and they have acted to expand those things during Obama's presidency - but it seems to be changes in attitudes that ignite party passions. Longstanding party priorities aren't as galvanizing as a hot new issue. Finally, there is some danger in identifying these changes as strictly partisan, if the term is exclusive to people who identify with a party. While the Pew survey found both major parties losing members to the hazy nondenominational category of "independents," that doesn't mean Democrats and Republicans are polarizing while a great disaffected middle shakes its head. Sorry, No Labels. Independents are mostly partisans who align ideologically with one party or the other while resisting the party label. Pew's figures on polarization didn't change when these "leaners" were factored in - an important caveat. Read the whole Pew report in all its chart-chocked glory.