Bill Clinton has been recorded going off-message and criticising the Israeli government’s unwillingness to seek peace with Palestinians in unguarded comments that contrast with other leading Democrats, including his wife, potential presidential candidate Hillary Clinton.

Speaking to a member of the public at a Democratic fundraiser in Iowa this weekend, the former president agreed with the suggestion that Israeli prime minister Binyamin Netanyahu was “not the guy” to strike a lasting peace deal in the region.

Clinton also agreed when it was suggested to him that “If we don’t force him [Netanyahu] to make peace, we won’t have peace”.

The former president replied: “First of all, I agree with that. But in 2000, Ehud Barack, I got him to agree to something I’m not sure I would have gotten Rabin to agree to, and Rabin was murdered for giving land to the Palestinians.”

Though brief and apparently unscripted, the exchange, which was recorded by C-Span and picked up by Israeli newspaper Haaretz, is in stark contrast to recent comments by Hillary Clinton, who has been more supportive of Netanyahu’s handling of the recent conflict in Gaza.

The Obama administration has also been less critical of Israeli policy of late, despite White House anger after the collapse of the 2013/14 peace process led by Secretary of State John Kerry – though it could possibly be dialling back any criticism out of fear of being accused of being soft on Islamist terrorism while it confronts militants in Syria and Iraq.

Even Massachusetts senator Elizabeth Warren, among the most liberal of the Democrats discussed as possible 2016 presidential candidates, has been become more hawkish following a visit to Israel and has publicly backed its behaviour in Gaza.

Whether Bill Clinton’s comments reflect the private thinking of these other leading Democrats is impossible to tell, but they also serve as a reminder that should Hillary Clinton run for president, the presence of a vocal and very opinionated spouse on the campaign trail creates added opportunity for embarrassment and even inadvertent policy shifts.

• This piece was amended on 16 September 2014 to make clear that Bill Clinton was agreeing with the assertion “If we don’t force him [Netanyahu] to make peace, we won’t have peace” and did not say those words himself. It also includes a fuller quote from Clinton to clarify he was listing advantages of earlier peace proposals to Palestinians, not Israelis.