"If you truly respect the Constitution, you will enforce it as written whether you like it or not," said Sessions.
"Our Constitution is very special," Liu told the committee today. "As a text, it's the permanent embodiment of the structure of government that we've chosen… the principles endure over the ages. Those things do not change, and the text does not change… What we argue in the book is that to preserve the power and meaning of that text, it's necessary for judges to give those phrases meaning in light of society."
The philosophy aligns him with more liberal justices on the Supreme Court, such as Justice Steven Breyer, and puts him at odds with conservatives like Justice Antonin Scalia, who as an "originalist" believes that in analyzing the constitutional text, one must give the text the meaning it had when it was adopted.
Conservatives worry that those who follow Liu's philosophy will find constitutional rights that are not set forth in the Constitution.
"Based on what I've read, I'm highly concerned," said Sen. Tom Coburn, R-Okla. "I think we have a completely different view of the Constitution."
M. Edward Whelan III, president of the Ethics and Public Policy Center, has written extensively about Liu's record on his blog in the National Review online.
"Liu has all the makings of a hard-Left judicial activist," says Whelan, "... as shown by his positions on matters ranging from welfare rights to racial quotas to same-sex marriage and by his utterly lawless constitutional philosophy generally."
Jonathan Singer, a current student of Liu, disagrees. "He's someone who has an open mind, not a doctrinaire ideologue," he said.
Liu today defended his writings, which he says have tended to be directed at policymakers, not judges.
"Whatever I may have written in the books and the articles will have no bearing on my role as a judge," he said. When asked if he would honor legal precedents set by the 9th Circuit Court of Appeals and U.S. Supreme Court, Liu said, "Absolutely, I would."
Liu , 39, who is the son of Taiwanese immigrants , sits on the board of the liberal American Constitution Society, and opposed the nominations of both Chief Justice John G. Roberts and Justice Samuel Alito. In an op-ed, Liu wrote that the nomination of Roberts "is a seismic event that threatens to deepen the nation's red-blue divide."
In 2006, Liu testified against the nomination of Alito, saying the judge had an "exceptionally talented legal mind," but that he was concerned with "Alito's lack of skepticism toward government power that infringes on individual rights and liberties."