Josh Hudder at Rule 22 claims that polarization in Congress is mostly a measurement phenomenon caused by the mid-1970s rule changes that led to more recorded procedural votes in the House and Senate. The argument goes that procedural votes are more partisan so if we observe more of them, measured partisan polarization would go up.

I have several reasons for being skeptical of this claim, but let me just share one. In the technical language of ideal point estimation, Hudder’s procedural argument is that the frequency of “cutpoints” that divide the parties went up increasing the measured polarization. The problem with Hudder’s argument is that scaling procedures like NOMINATE and Bayesian IRT are fairly insensitive the the distribution of cutpoints. What really matters is that there are at least some cutpoints that separate each pair of adjacent legislators. In other words, suppose we estimated ideal points from a set of roll calls that have cutpoints between each pair of members. If we then added a zillion party line votes, estimated polarization would not change that much (it might reduce some overlap but it would not necessarily move the party means or medians apart).

The right experiment would be estimate polarization holding the distribution of cutpoints constant or vote margins. This experiment is conducted in chapter 2 of my book with Poole and Rosenthal. We found that the counterfactual polarization measures (those holding the margins distribution constant) correlated with the observed measures at greater than .95.

I also refer readers to Alex Hirsch’s recent paper in Political Analysis which also shows the robustness of ideal point estimates to changes in the distribution of cutpoints.

The New Jersey Redistricting Commission announced its congressional district maps this morning. Much of the focus will be on the fact that the independent commissioner John Farmer accepted the GOP proposal which included a match up of Republican Scott Garrett and Democrat Steve Rothman in what is essentially Garrett’s old district. So barring the unthinkable, like Ron Paul being the GOP nominee, the Democrats will lose a seat.

But I am more interested in the other features of the outcome. Despite Commissioner Farmer’s earlier stated aspirations to use redistricting as a platform to increase competition and reduce polarization, this appears not to have happened. In fact, none of the other New Jersey representatives are in danger of losing, and Farmer himself lauded the plan for creating “continuity in representation.” Moreover, two freshman members Leonard Lance and Jon Runyan were given better districts, potentially eliminating two tough reelection bids.

But that is just fine by me. As I have written here previously, the notion that polarization can be addressed by districting has almost zero support among political scientists. Moreover, the creation of artificially competitive districts violates important norms of representation and may even backfire as I argue here.

For me at least, one of the frustrations about the debate over extending the cut in the payroll tax is extent to which politicians have tried to exploit the public’s lack of understanding about how the Social Security system works.

The first lie is the Republican claim that extending the payroll tax will somehow deprive the Social Security system of funds and jeopardize the retirement security of seniors.

Democrats have responded not with the truth but with the claim that the revenue losses from the extension will be offset by “general revenue.”

Understanding why both of these claims are untrue requires some background knowledge of how Social Security works.

Social Security is a pay-as-you-go system where current retirees are supported by the payroll tax payments of current workers. When I pay payroll taxes, they do not go into some account with my name on it, they go to my mother-in-law. Every year since 1984, the payroll tax revenues plus interest on the SS Trust Fund’s holding of treasury notes has exceeded the benefits paid out. The Trust Fund then exchanges this surplus for more treasury bills and the federal government spends it.

In 2010, the Trust Fund surplus was $94 billion or about 16% of the benefits paid. That is about the same size as the revenue short fall from the 2 point reduction in the payroll tax rate (the SS Trustees estimate a loss of about $90b for 2011). So even with this loss, payroll taxes and interest will cover the benefits paid. So one of two things will happen. The Treasury will actually give $90b to the Trust Fund. But because it is surplus, the Trust Fund will give it right back to Treasury in exchange for government debt. Or it could be handled the easy way: Treasury would just give the Trust Fund $90 billion in Treasury notes.

The important point is that the effect of the payroll tax cut on the balance sheet of the Social Security Trust Fund is exactly zero. With or without the cut in 2011, the Fund would increase its holding of U.S. government debt by over $90 billion. Even if the government did not give the Trust Fund the $90 billion worth of debt, the effects would not be felt until around 2035 when the Trust Fund is expected to be exhausted.

Thus the Republican claims have no merit.

I’ll admit the Democratic shading of the truth is less egregious. It is easier to say that general revenue will cover lost payroll tax revenue than it is to explain that the government will only promise to pay it back later by issuing more debt. But I do think, the Democratic rejoinder is problematic on two accounts.

First, it seems to suggest that the current funding of Social Security is more perilous than it really is. It would have been more comforting to point out that the system takes in so much money that it could pay out all promised benefits even with the lost revenue.

Second, the Democrats missed an opportunity to raise the public’s understanding of the longer-term problems with Social Security. The years of surplus will come to an end at some point. Already (and independent of any payroll tax cuts), benefit payments exceed payroll tax revenues so that the surplus is being generated by interest on government debt. At some point in the next decade, tax revenues plus interest will no longer be enough and the system will have to start redeeming its $2.5 trillion stash of Treasury notes. At this point, general revenues will indeed start flowing out to Social Security recipients, placing increasing strain on the federal budget that will also be coping with escalating Medicare costs.

Peter Orzsag on State Legislative Polarization. A very good summary of the research, but it emphasizes the role of residential and geographic sorting a bit much for my taste.

Some of my recent (and very tentative) work with Boris Shor, Chris Warshaw, Chris Tausanovitch, and Jonathan Rodden sheds some light on the question of the role of residential sorting (beyond my general skepticism borne of the null findings for Gerrymandering).

In our presentation at the American Political Science Association (unfortunately there is not yet a manuscript), we used Tausanovitch and Warshaw‘s estimates of 245,000 voter ideal points to construct measures of the distribution of voter preferences in every Senate. We then combined this data with my and Boris’s data on state senator ideal points to estimate the relationship between within-district voter heterogeneity and polarization. A taste of our findings is available after thr jump.

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