Pity Larry Lowenthal. His job as executive director of the Boston branch of the American Jewish Committee (AJC) includes finding and training leaders from among the 700,000 Russian Jews who have immigrated to the U.S. in the last 30 years. Mr. Lowenthal has fared well: Today there are Russians helping to guide a number of major Jewish organizations, like the one called Boston for Israel. But now these immigrants turn out to be … oh no! Republicans! To judge by his public statements and writings, Mr. Lowenthal's idea of a faithful Jew is someone who opposes the nomination of Judge...