Stat Of The Week: SCOTUS 'Loyalty Effect'

SCOTUS justices more frequently vote for the government’s side when the president who appointed them is in office.

In theory, the Supreme Court is meant to be the most dispassionate of government institutions, far above personal whimsy or the vulgarities of partisan politics. But the justices are, of course, mere humans. Professors Lee Epstein and Eric Posner have released a new paper demonstrating one interesting aspect of the justices’ humanity: loyalty to the presidents who appointed them. The paper, Supreme Court Justices’ Loyalty to the President, offers a statistical analysis of voting by Supreme Court justices from 1937-2014 showing evidence of a “loyalty effect.”

Broadly speaking, SCOTUS justices more frequently vote for the government’s side when the president who appointed them is in office than when subsequent presidents lead the government, even when subsequent presidents are of the same party as the justices. The authors found that the loyalty effect is much stronger for Democratic justices than it is for Republicans.

The data organizes itself into a striking U-shaped time trend. The x-axis shows the initials of justices in chronological order. The y-axis shows a measure of preference for the government under the appointing president over subsequent governments. (Note that Obama and Bush appointees are excluded.)

The loyalty effect is quite pronounced for FDR’s appointments, then low for the period extending from Truman to the 1970s, and then climbs higher thereafter. Check out the whole fascinating paper here.

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