The tenor of debate at the Supreme Court has changed since two justices, appointed by President Barack Obama, have joined the nation's highest judicial body. For the first time in 20 years, there are liberal voices to stand up to the questions of Justice Antonin Scalia who is sometimes caustic and always conservative. In the past, the views of the left were given voice by soft-spoken justices like David Souter and John Paul Stevens. Now, Sonia Sotomayor and Elena Kagan are bringing new energy to debates. "They're clearly on a roll," said one Washington lawyer. "They are engaged and really active. It just feels like a different place."