Across party lines, the pick of Elena Kagan is not as well received as that of Sonia Sotomayor, according to Gallup's instant polling.

Kagan is viewed favorably by 63 percent of Democrats, 35 percent of independents, and 18 percent of Republicans. After her nomination, Sotomayor impressed 72 percent of Democrats, 40 percent of independents and 29 percent of Republicans.

Part of the problem is that more people have "no opinion" of Kagan, who doesn't offer as vivid a personal story as Sotomayor. The 24 percent of respondents who have no opinion of Kagan is the highest recorded by Gallup since it began reviewing instant reaction in 2005, when 15 percent offered no opinion of John Roberts.

A comparison of Gallup's findings over the years: