Partisan Polarization: A Threat to US Foreign Policy?

Does partisan polarization threaten to undermine US foreign policy-making? Since 1945 US foreign policy has been based on a liberal internationalist consensus blending cooperative/consensual elements (support for international institutions, foreign assistance, and free trade) with coercive ones (defence spending, military superiority, and the use of force). This consensus has been sustained by the dominance of both parties by centrist politicians who recognize the necessity of both dimensions to a successful foreign policy.

Increasing partisan polarization, however, has led to fears that the centre ground is being abandoned, with Democrats backing only the consensual  tools of foreign policy whilst Republicans reject them in favour of coercive measures. The potential consequences of that development are the replacement of the liberal-internationalist consensus by a foreign policy characterised by deep swings between cooperative and hardline policies and increasing foreign policy gridlock as the partisan opposition in Congress seeks to block presidential initiatives.  Both outcomes would clearly impinge on the ability of the USA to construct a coherent foreign policy (

Those consequences, however, depend on polarization actually existing in the first place. Whereas there is a broad consensus in regard to the polarization of American domestic politics (, there is disagreement between those who believe that partisan polarization has also become the foreign policy norm (, and those who argue that the liberal-internationalist consensus remains intact (

As a first step toward evaluating the consequences of polarization for US foreign policy, therefore, it is necessary to develop an accurate picture of the extent to which policy-making behaviour is, or is not, polarized.

We therefore analysed votes in the House of Representatives between 1970 (the date after which it is alleged that foreign policy polarization began to increase) and 2013 utilising a variety of indicators. Firstly, we employed the standard indicator utilised in most studies of polarization, the party unity vote, which measures the percentage of time in each year that a majority of Democrats opposed a majority of Republicans on foreign policy votes. In addition to this we measured the level of party unity votes on foreign policy relative to domestic policy on the assumption that if levels of unity on the former increasingly approached those on the latter this would indicate increasing polarization. Thirdly, we ran the analysis looking only at votes on which the president had expressed a position.  A key criticism of the argument that polarization now characterizes congressional foreign policy voting is that this is simply a methodological consequence of including all votes, whether important or trivial, in the analysis. By using only presidential position votes we were able to test this claim (presidents rarely express a position on insignificant legislation). Finally, we employed a static indicator which measured whether Congress was polarized at any  specific point in time.

When we ran the analysis we found that the analyses of party unity using all votes on the one hand and only presidential position votes on the other both tell a similar story of an initial increase in polarization through the 1970s and into the 1980s, a levelling off and subsequent decline in polarization from the late 1980s, followed by a another upturn in polarization from the mid 2000s.

The comparison of domestic and foreign policy voting was equally inconclusive. In the 1970s, foreign policy voting was increasingly more partisan than domestic policy voting. The difference declined gradually in the 1980s and partisanship on foreign issues fell back towards the levels of partisanship on domestic issues in the 1990s. The new century witnessed a continuation of this trend only for it to turn back towards partisanship once again in the late Bush and Obama presidencies.

The data analysis examining foreign policy polarization at specific points in time returns similarly complex results. The analysis utilising presidential position votes demonstrates that House voting on foreign policy issues has been polarized for a clear majority of the time since 1970 while the analysis of all votes shows polarization becoming the exception rather than the rule since 2000.

Our conclusion, therefore, is that the existing alternatives presented in the literature on foreign policy polarization—new norm or myth—are too simplistically drawn. Congress is not polarized or polarizing on foreign policy issues; nor is it not polarized or becoming less polarized.

What remains is the problem of accounting for this rather complex set of results. Two potential lines of analysis suggest themselves. Either, contra most of the existing arguments, the causes of polarization are not permanent and ongoing but rather fluctuate over time or, more likely, the effects of polarization are qualified by those of one or more intervening variables (divided government, partisan identity of the president, economic growth levels, the changing issue agenda), which means we need to develop more sophisticated models in order accurately to capture the effects of partisan polarization on foreign policy.

Dr Steven Hurst is a Reader in Politics in the Department of History, Politics and Philosophy
at Manchester Metropolitan University

Matthew Hill