This article examines online recruitment via Facebook, Mechanical Turk (MTurk), and Qualtrics panels in India and the United States. It compares over 7300 respondents—1000 or more from each source and country—to nationally representative benchmarks in terms of demographics, political attitudes and knowledge, cooperation, and experimental replication. In the United States, MTurk offers the cheapest and fastest recruitment, Qualtrics is most demographically and politically representative, and Facebook facilitates targeted sampling. The India samples look much less like the population, though Facebook offers broad geographical coverage. We find online convenience samples often provide valid inferences into how partisanship moderates treatment effects. Yet they are typically unrepresentative on such political variables, which has implications for the external validity of sample average treatment effects.

The 2012 challenge to the Affordable Care Act was an unusual opportunity for people to form or reassess opinions about the Supreme Court. We utilize panel data coupled with as-if random assignment to reports that Chief Justice Roberts's decision was politically motivated to investigate the microfoundations of the Court's legitimacy. Specifically, we test the effects of changes in individuals' ideological congruence with the Court and exposure to the nonlegalistic account of the decision. We find that both affect perceptions of the Court's legitimacy. Moreover, we show that these mechanisms interact in important ways and that prior beliefs that the Court is a legalistic institution magnify the effect of updating one's ideological proximity to the Court. While we demonstrate that individuals can and did update their views for multiple reasons, we also highlight constraints that allow for aggregate stability in spite of individual-level change.

The formal institutional constraints that Congress and the courts impose on presidential unilateral action are feeble. As a result, recent scholarship suggests that public opinion may be the strongest check against executive overreach. However, little is known about how the public assesses unilateral action. Through a series of five survey experiments embedded in nationally representative surveys, we examine the extent to which Americans evaluate unilateral action based on constitutional, partisan, and policy concerns. We find that Americans do not instinctively reject unilateral action as a threat to our system of checks and balances, but instead evaluate unilateral action in terms of whether it accords or conflicts with their partisan and policy preference priors. Our results suggest that the public constraint on presidential unilateral action is far from automatic. Rather, the strength and scope of this check are variable products of political contestation in the public sphere.

I nterest groups often make their preferences known on cases before the U.S. Supreme Court via amicus curiae briefs. In evaluating the case and related arguments, we posit that judges take into account more than just the number of supporters for the liberal and conservative positions. Specifically, judges' decisions may also reflect the relative power of the groups. We use network position to measure interest group power in U.S. Supreme Court cases from 1946 to 2001. We find that the effect of interest group power is minimal in times of heavily advantaged cases. However, when the two sides of a case are approximately equal in the number of briefs, such power is a valuable signal to judges. We also show that justice ideology moderates the effect of liberal interest group power. The results corroborate previous findings on the influence of amicus curiae briefs and add a nuanced understanding of the conditions under which the quality and reputation of interest groups matter, not just the quantity.

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