The Senate Judiciary Committee is holding hearings on Goodwin Liu’s nomination to the 9th Circuit Court of Appeals in San Francisco today and conservatives are on 10 about it. If approved, Liu will be the only Asian-American judge serving in the nation’s appellate courts. But conventional wisdom is that this is a test debate for the coming Supreme Court battle. As Democratic Sen. Ted Kaufman declared as he opened his questioning this morning, “Welcome to the Judiciary Committee and the Supreme Court confirmation process.” But the appeals court nomination itself is terribly important. For decades, Republican presidents have made a priority of stacking the lower federal courts with ideologues. As a result, conservative legal activists have shaped the lower courts, which rule on far more cases and shape what funnels up to the Supreme Court — including nominees for justices. Indeed, some argue Republicans’ fierce opposition to Liu is about cutting off his road to the high court. Republicans on the committee argue that Liu deliberately submitted a too-thin response to a questionnaire about his work and views. They’re working hard to define Liu as a radical judicial activist and seem to be stirring speculation he’s got something to hide. Sen. Diane Feintstein countered this morning with a long list of George W. Bush appointees who provided dramatically thin responses to the questionnaire; those included Chief Justice Roberts, who didn’t answer 75 percent of the questions. Watch the C-SPAN rebroadcast of the hearing here.