(Radio Iowa) -Iowa Senator Chuck Grassley is joining fellow Republicans in opposing an effort to temporarily replace Senator Diane Feinstein on the Judiciary Committee, as the California Democrat extends her leave of absence due to a bout with shingles.

Grassley denounces Senate Leader Chuck Schumer, who’s asking for a so-called “courtesy” move that would see Democrats appointing someone else to that powerful panel for a matter of several weeks. “I’m very, very skeptical that we should bow to Schumer using senatorial courtesy,” Grassley says, “when he wants to do it just for a short period of time to get very liberal judges on the bench.”

Grassley says Feinstein is being singled out because of her age. She’s 89, the same age as Grassley. “If it was a permanent replacement of Feinstein on that committee, plus all the other committees she’s on, I can understand that,” Grassley says, “but I’m not inclined to buy that argument today.” Grassley says it’s “just a cruel thing” to say Feinstein is incapable of performing her duties and he’s confident she’ll return soon. She’s already been out for six weeks and is recovering at home.

“When Democrats boast about being for women’s issues, and for older people, I don’t think they have a leg up on Republicans in regard to that, but we don’t brag about it as they do,” Grassley says. “And now they’re going after her because she’s 89 years old.”

Feinstein, the oldest current member of Congress, is about three months older than Grassley.