Bernie Sanders has defended his rival for the Democratic presidential 2020 nomination, Elizabeth Warren, after her policy against pre-emptive use of America’s nuclear weapons was attacked by the daughter of one of the architects of the Iraq war.

Warren reiterated her support for a “no first use” policy on nuclear weapons during the second round of Democratic presidential debates this week.

“It makes the world safer,” the Massachusetts senator said during the debate. “The United States is not going to use nuclear weapons pre-emptively, and we need to say so to the entire world.”

Liz Cheney, a Republican congresswoman from Wyoming, attacked Warren’s policy on Twitter, asking “which American cities and how many American citizens are you willing to sacrifice with your policy of forcing the US to absorb a nuclear attack before we can strike back?”

Cheney is the daughter of former vice-president Dick Cheney, a key advocate of the 2003 invasion of Iraq by the United States and its allies.

The Bush administration’s primary justification for the pre-emptive war, that Saddam Hussein had weapons of mass destruction and that his regime presented an escalating threat, was discredited after the invasion.

The war in Iraq, now in its 16th year, has resulted in an estimated 200,000 documented civilian deaths from violence, according to Iraq Body Count, although estimates vary widely, particularly estimates that factor in hundreds of thousands of additional war-related civilian deaths. More than 4,000 members of the US military have been killed.

Taking national security advice from a Cheney has already caused irreparable damage to our country. We don't need any more, thanks. https://t.co/pHr5TM9UgX — Bernie Sanders (@BernieSanders) August 2, 2019

“Taking national security advice from a Cheney has already caused irreparable damage to our country,” Sanders wrote on Friday, in response to Cheney’s attack on Warren.

The Democratic congresswoman Alexandria Ocasio-Cortez, who was 13 years old when the Iraq war began in 2003, also responded to Cheney’s attack on Warren, criticizing Cheney for offering hawkish foreign policy advice “as if an entire generation hasn’t lived through the Cheneys sending us into war since we were kids”.

MFW *Liz Cheney* of all people tries to offer foreign policy takes, as if an entire generation hasn’t lived through the Cheneys sending us into war since we were kids: https://t.co/xrOCN1c9OI pic.twitter.com/8Hoq1NbMC9 — Alexandria Ocasio-Cortez (@AOC) August 2, 2019

Liz Cheney’s response to the criticism of her father’s push for pre-emptive war was to call Sanders a “commie” with “daddy issues”.

No surprise commie @BernieSanders, who honeymooned in Soviet Union, is ok with U.S. getting attacked first. (On a side note, he seems to have daddy issues...with my daddy.) https://t.co/OdbbvdyvV6 — Liz Cheney (@Liz_Cheney) August 2, 2019

Cheney’s attack on Warren echoed the response of one of Warren’s Democratic rivals during the debate, the Montana governor, Steve Bullock, who said he did not support a “no first use policy” because, “I don’t want to turn around and say, “Well, Detroit has to be gone before we would ever use that.”

The Washington Post columnist Elizabeth Bruenig also argued “you can’t have daddy issues with someone else’s daddy.”

you can't have daddy issues with someone else's daddy. if you don't like someone else's daddy, that's just ordinary beef https://t.co/Ar8bkSkN31 — elizabeth bruenig (@ebruenig) August 3, 2019

During the 2016 presidential campaign, Trump repeatedly expressed some reluctance to use nuclear weapons first, but also said he did not “want to rule out anything”. At a debate in September of that year, Trump said, “I would certainly not do first strike” but in the sentence that followed that statement, he said: “I can’t take anything off the table.”

As Slate’s Fred Kaplan noted, the Trump administration’s 2018 Nuclear Posture Review maintained the Obama administration’s language on first use policy – not ruling it out completely, but suggesting it would be only used in limited circumstances.

“It remains the policy of the United States to retain some ambiguity regarding the precise circumstances that might lead to a U.S. nuclear response,” the 2018 review notes.