Sen. Ben Nelson on Friday broke ranks with his fellow Democrats and announced he would oppose the Supreme Court nomination of Solicitor General Elena Kagan.

Although the Nebraska lawmaker said in a statement he would oppose a filibuster of her nomination, he said her lack of experience makes her unqualified.

“I have heard concerns from Nebraskans regarding Ms. Kagan, and her lack of a judicial record makes it difficult for me to discount the concerns raised by Nebraskans, or to reach a level of comfort that these concerns are unfounded. Therefore, I will not vote to confirm Ms. Kagan’s nomination,” Nelson said.

Nelson is the only Democrat expected to vote against Kagan.

His decision angered fellow Democrats, who have become increasingly frustrated by his rightward tack over the last several months, going back to the debate over health care reform.

“It’s a very transparent political move to cover his own tracks on a health care deal that he pushed at his own choosing,” said a Senate Democratic aide, referring to a provision in the health care bill derided by Republicans as the “Cornhusker Kickback,” which Nelson negotiated and later repudiated.