With the New York senator's husband, former President Bill Clinton, taking a more active role in her campaign for the Democratic presidential nomination, recent attack ads frequently have focused on her chief rival, Sen. Barack Obama, D-Ill., The Washington Post reported.
Senate Judiciary Chairman Patrick Leahy, D-Vt., who endorsed Obama last week, criticized Bill Clinton for what he called his "glib cheap shots" at Obama.
"That's beneath the dignity of a former president," Leahy told reporters. "He is not helping anyone, and certainly not helping the Democratic Party."
Sen. Mary Landrieu, D-La., who is not aligned with any of the contenders, said party unity was being threatened by the escalating attack ads.
"Our party has to remain united -- that's the most important thing for November," she said. "The bottom line is, all this could cause a rift, but I hope it doesn't."