With Obama sorting through about 10 potential nominees — including Kagan’s friend, the current Harvard Law School dean, Martha Minow — it is too early to gauge how Kagan’s chances of getting picked are being affected. But the complaints have grown loud enough that the White House, while declining to comment publicly, has begun providing background information to reporters in a bid to bolster her against charges from the left.

Kagan, who has never been a judge, lacks a trail of courthouse decisions, which activists of all stripes say makes it difficult to fully gauge her views.

A chief complaint from liberals stems from her statement during her 2009 confirmation hearing to be solicitor general, during which she agreed with a Republican senator, Lindsey O. Graham of South Carolina, who said the government could hold suspected terrorists indefinitely without trial.

Fighting such detentions has been a major cause of many legal scholars, rights groups, and Democrats. She also is paying the price for positions taken by the Obama Justice Department, which has continued to defend Bush administration legal positions on warrantless wiretapping, detainees, and government secrecy.

“They’re upholding all these reprehensible Bush antiterrorism policies that have been condemned by every human rights and civil liberties organization in the country,’’ said Francis Boyle, a professor of international law at the University of Illinois. “There has been no retreat by Kagan. She could have backed off on all these Bush positions and she refused.’’

Kagan’s 2009 confirmation, however, mostly illustrated how she is difficult to pigeonhole ideologically.

A Democratic senator, Amy Klobuchar of Minnesota, marveled during hearings that Kagan had “managed to get a standing ovation from the Federalist Society at Harvard,’’ referring to a conservative group that believes in strict interpretation of the Constitution. But during the same proceeding, Kagan declared that the greatest lawyer of the 20th century was the late Supreme Court justice Thurgood Marshall, a liberal for whom she clerked.

She rebuffed efforts by senators who sought to draw out her views on the death penalty, for instance — potentially good training for the issue-avoidance rituals that are even more pronounced during Supreme Court confirmation hearings.  Continued...