Donald Trump is assembling his war cabinet. The appointment of John Bolton as national security adviser – following the nomination of CIA director Mike Pompeo as secretary of state – could be the beginning of Trump’s march to war. Or wars.

The timing is not coincidental. In May, Trump will likely rip up the diplomatic agreement that has prevented Iran from getting a nuclear weapon, sparking a period of heightened tensions with Iran and removing one of the final barriers to escalating military conflict with Iran across the Middle East.

If Trump’s upcoming summit meeting with North Korean leader Kim Jong-un fails – as is highly likely – the next step could be preventive military action.

Two wars, on two fronts, with incalculable costs.

If you’re not scared yet, you should be. John Bolton has been thinking about this for a long time.

In 1998, Bolton signed a letter encouraging then president Bill Clinton to invade Iraq. As undersecretary of state for arms control and international security affairs from 2001 to 2005, Bolton was a senior George W Bush administration official helping orchestrate the invasion of Iraq.

As one career state department official who worked with Bolton wrote, “John Bolton was a key player in the early machinations toward war of the George W Bush administration” who “knew very well how the administration was misrepresenting” the intelligence about the existence of Iraqi weapons of mass destruction (WMD). Not even years of catastrophe in Iraq after the invasion sobered Bolton’s views: he said in 2015: “I still think the decision to overthrow Saddam was correct.”

That Trump – who claimed (falsely) to have opposed the Iraq war – named Bolton his national security advisor just days after the 15th anniversary of the beginning of the invasion of Iraq is some very sick irony.

Today, John Bolton has new targets.

Iran is in Bolton’s sights. In 2015, Bolton wrote an op-ed advocating military strikes on Iran, claiming that: “The inconvenient truth is that only military action like Israel’s 1981 attack on Saddam Hussein’s Osirak reactor in Iraq or its 2007 destruction of a Syrian reactor, designed and built by North Korea, can accomplish what is required.”

And just when one thought that Trump’s embrace of diplomacy with North Korea might have indicated a new, more peaceful direction in US policy, Bolton’s entrance to the White House should disabuse everyone of that notion.

Bolton supports preventive military strikes against North Korea: “It is perfectly legitimate for the United States to respond to the current ‘necessity’ posed by North Korea’s nuclear weapons by striking first.” In a recent appearance on Fox News, Bolton appeared to hint that if Kim doesn’t come to the table ready to hand over his nukes, military action could follow.

Some may claim that this is yet another chaotic staff change in a White House where all staff is eventually discarded, and the only opinion that matters is that of Trump. And that may very well be true. But with such a reckless, impulsive president, all that stands between Trump and disastrous wars is a short meeting with his advisors to place the orders.

The appointment of John Bolton just moved America one very large step closer to that disastrous moment. Bolton may be a radical, but he’s not incompetent. He’s a weekly feature on Fox News, practically providing Trump his presidential daily briefing. He is a highly skilled bureaucratic fighter. It doesn’t take much to imagine Bolton in the Oval Office telling Trump to bomb Iran and North Korea; that Obama didn’t have the guts to do it; that it will cement his place in history.

The job of the national security advisor is to work with the relevant US government agencies to compile policy options for the president. There’s no reason to believe that Bolton will push anything but his own radical views, as illustrated by his cherry-picking of Iraq intelligence while at the state department. With Mike Pompeo – a hawk on Iran and North Korea, and a true Trump enabler – likely headed to State, the internal obstacles to catastrophic military decisions are being removed.

Secretary of defense James Mattis – with his relatively moderate views on matters of war and peace – now could be the last man standing between America and the abyss.

This is not only a time for concern, but also for action. Every American needs to speak out against this appointment. While Bolton’s new position does not require Senate confirmation (Bolton was so radical he could not get confirmed by a Republican Senate in 2005), Trump must hear a chorus of voices in Congress express grave concern and make clear that they will act to prevent Trump from starting unnecessary wars.

The Senate must vote down the nomination of Pompeo. This is a genuine national emergency.