Former Iowa Sen. Tom Harkin — a prominent Hillary Clinton-backer in the nation’s first caucus state — jabbed at her rival today, saying insurgent democratic socialist candidate Bernie Sanders is just as “establishment” as Clinton is.

“Bernie Sanders has been in public office longer than Hillary Clinton, what makes him not establishment?” Harkin told “Morning Meeting” hosts Jaclyn Cashman and Hillary Chabot on Boston Herald Radio. “He’s establishment too. If you want non-establishment you should vote for Dr. Carson or that Trump character.”

Harkin served in the Senate with both Clinton and Vermont Sen. Bernie Sanders — who served as mayor of Burlington, Vt., and in the House of Representatives before becoming a senator in 2007. While Sanders leads in most recent New Hampshire polls, Clinton is ahead in Iowa, which caucuses on Feb. 1.

“The reason Bernie is doing so well is because he is speaking to a lot of unmet needs we have in this country and how short we are of the promise of America,” Harkin said. “(Clinton) has a better global understanding, better than anyone in my lifetime that has ever run for president. I think it’s unfair to say that somehow she is not addressing those issues of inequality, she is.”

Harkin said he believes Clinton will win the caucuses.

“Bernie is going to do well there, don’t get me wrong, but we are going to win the Iowa caucus for Hillary Clinton,” he said. “I can’t speak to New Hampshire because I haven’t been there, but I think it’s clear Hillary Clinton is going to be the nominee and I think she is going to be our next president.”

Harkin also praised the handling of the Benghazi attack by the then-Secretary of State as well as other government agencies — the subject of years of controversy and congressional hearings.

“This whole Benghazi thing was handled absolutely correctly by everybody — the military, the CIA and the state department … nobody really knew what was going on at that time,” Harkin said. “That Benghazi hearing, I watched a lot of it, and Hillary showed she can maintain her composure and think clearly when she is under a great deal of fire.”

House Republicans grilled the Democratic frontrunner for nearly 11 hours a little more than a week ago about her handling of the 2012 attack on an American diplomatic compound in Benghazi, Libya, that left four Americans dead.

The Iowa Democrat accused Republicans of “overplaying their hand” when it comes to slamming Clinton for Benghazi.

“Their hatred of the Clintons almost knows no bounds,” Harkin said. “If you look at the Republican debates, they are going after Hillary Clinton because they know she will be their toughest opponent. Whatever they can do to destroy her, to cut her down, to demean her, that’s what they are doing. Pretty soon the American people are going to say ‘enough already. What do you stand for? What are you trying to do? Quit trying to tear down Hillary Clinton like you’ve been trying to do for years.’ ”

On the subject of debates, Harkin said he didn’t think the much-maligned CNBC Republican debate was the toughest the GOP field has faced.

“The first debate was with FOX News — this is the arm of the Republican party — I thought they were tougher,” he said. “FOX was very tough on the questions for their own side. My gosh, they had really tough questions.”

Harkin did call out the performance of CNBC’s John Harwood, Becky Quick and Carl Quintanilla, who moderated the latest Republican debate and drew sharp criticism from the candidates who accused them of bias.

“I thought the questioners were not up to task and they lost control of the debate,” Harkin said. “I thought some of the questions were ridiculous.”