Supreme Court nominee Sonia Sotomayor faced some of her most difficult questioning from an unlikely source — Democratic Sen. Russ Feingold (Wis.) — as she slowly worked through her Judiciary Committee confirmation hearing Tuesday afternoon.

While Republicans struggled to throw Sotomayor off-stride by repeatedly questioning her about racial issues, Feingold appeared to be the lone lawmaker to actually push her.

Feingold pressed Sotomayor on her Second Amendment rulings and opinions on gun ownership, probing to see if she would acknowledge that citizens have a constitutional right to bare arms.

Sotomayor repeatedly ducked those questions, arguing that because the Supreme Court will likely rule on these issues in the coming years, she could not comment directly on them.

“You are a very eloquent advocate. … But a decision of what the Supreme Court will do will come up before the justices in great likelihood in the future,— she said, adding that, “The court ruled that under the Second Amendment there is a personal right to bear arms and that is … holy and that is the court’s decision, and I fully accept that.—

Republicans had much less luck in putting Sotomayor in an uncomfortable position. Sen. Chuck Grassley (R-Iowa) kicked off the afternoon session focusing almost exclusively on her position on property rights — a parochial issue for the farm state Grassley.

Likewise, Senate Minority Whip Jon Kyl (R-Ariz.) made little headway despite his repeated questioning about previous statements by Sotomayor that conservatives charge demonstrate she is biased toward minorities, women and the poor.

At one point, Kyl asked Sotomayor whether she agrees with President Barack Obama’s contention that judges should demonstrate “empathy— for the poor or minorities.

“No sir,— Sotomayor said, arguing that while judges should be able to understand the implication of their rulings, that should not dictate how they rule. “Judges can’t rely on what’s in their hearts. They don’t determine the law. Congress makes the law. … It’s not the heart that compels decisions in cases. It’s the law.—

“We apply law to facts. We don’t apply feelings to facts,— she added.