Party affiliation serves as a measurable proxy for a judge’s unobservable political attitudes.

Evidence

If political attitudes affect the votes of judges on the U.S. Supreme Court, presumably they should on other courts as well. This is difficult to confirm directly, however, because state and federal judges do not grant interviews to discuss their political views. Researchers have therefore approached the issue indirectly, often by looking for connections between judges’ party affiliations and their voting behavior. This research assumes that because Republicans and Democrats have different political perspectives, party membership will be a good indicator of judges’ attitudes: Republican judges will be more conservative and Democratic judges more liberal. Therefore, if judges’ attitudes decisively influence their votes, one should be able to predict the overall pattern of their votes by knowing the judge’s party affiliation. — G. Alan Tarr, Judicial Process and Judicial…, 2587

Categorization

• DEFINE: Explains the operationalization behind party-affiliation research: party ID stands in for attitude because judges will not be interviewed.
• XREF: connects to: Most appeals court judges were politically active in the appointing president’s party — G. Alan Tarr, Judicial Process and Judicial…, 471