"She doesn't have any foreign policy credentials," the Nebraska Senator told the Omaha World Herald on Wednesday. "You get a passport for the first time in your life last year? I mean, I don't know what you can say. You can't say anything."
Republican presidential nominee John McCain and other republicans have defended the Alaska governor's qualifications by noting her state's location next to Russia.
"I think they ought to be just honest about it and stop the nonsense about, 'I look out my window and I see Russia and so therefore I know something about Russia,'" the Nebraska senator said. "That kind of thing is insulting to the American people."
Hagel has previously said he would have considered being Democratic presidential candidate Barrack Obama's vice president pick, although he had not expected to be asked.
Palin recently defended herself against charges that she doesn't have enough foreign policy experience.
"We've got to remember what the desire is in this nation at this time," she said in an interview with ABC News. "It is for no more politics as usual, and somebody's big, fat résumé, maybe, that shows decades and decades in that Washington establishment where, yes, they've had opportunities to meet heads of state."
"I'm ready," Palin said. "I have the confidence in that readiness and knowing that you can't blink."