WASHINGTON – The Senate’s top Republican said U.S. Supreme Court nominee, Sonia Sotomayor of the U.S. Court of Appeals for the Second Circuit, fails the test of impartiality despite her impressive background, while the senior Democrat defended her as a mainstream moderate, as the Senate prepared to debate the judge expected to be confirmed as the first Hispanic and third female justice.

Republican Senator Mitch McConnell of Kentucky and Democratic Senator Harry Reid of Nevada previewed their parties’ dueling arguments Tuesday over President Barack Obama’s nominee, who is expected to sail through the Senate this week with bipartisan support. Most Republican senators have lined up against Judge Sotomayor, but a handful are siding with Democrats to support her.