Just a few days ago, Brent Scowcroft celebrated his 93d birthday. He is not in the best of health. His days on the public stage are behind him.

But for those who study American power and leadership in the modern era, the slender, quiet former Air Force lieutenant general remains a giant. He established the standard by which all will be measured who hold the office of national security adviser to which John Bolton was just named. And understanding the reasons for Scowcroft’s success is the key to understanding why Bolton is such a disturbing, devastatingly bad choice for the job.

Scowcroft is the only person to have served as national security adviser twice—once under President Gerald Ford and once under President George H.W. Bush. Innumerable factors led to his success in the job. But of these a few stand out. They were his world view, his temperament, his respect for process and systems, his respect for his colleagues and the regard in which they held him, his management skills, and his relationship with the presidents he served.

In each of these vital characteristics, not only does Bolton fall short, he does so spectacularly. Indeed, you might well say that if Scowcroft is the gold standard among national security advisers, then Bolton is fool’s gold.

World view may seem a vague term. But one of the unifying characteristics I have noted about all those who have distinguished themselves among America’s foreign and national-security policy leaders is that they carefully cultivated their view of the planet every single day of their lives. Men like Scowcroft, Kissinger, Brzezinski, and Shultz would wake up and study the news and recalibrate their sense of the planet, shifting power, and America’s role and interests. Perhaps Bolton does that. But world view is more than that.

For the past 75 years, America’s leaders have sought to create an international system of institutions and laws that would reduce the risk of conflict, protect public goods and spread core ideas like democracy, human rights, and free markets. Those leaders have seen it as essential that America invest in the development of that system—because it was in our national interest to do so, because it made the world safer and more prosperous and benefited every American citizen as a consequence.

“ Bolton seems likely to exacerbate Trump’s worst impulses while failing to offer him the counsel he desperately needs. ”

Donald Trump is overseeing a dramatic shift away from that ideal. He is promoting a nationalist view without precedent since the end of the Second World War. He is undercutting international institutions, withdrawing from treaties, undermining alliances, and acting unilaterally in a way that is without modern precedent. And he has hired Bolton precisely because he shares the same views.

Bolton has shown contempt for the international system since before he became U.S. U.N. Ambassador under George W. Bush in 2005. It is one reason 100 former diplomats opposed his nomination to that job and that a Republican-controlled Senate would not confirm him (he became a recess appointment).

His belief in the most extreme, distorted view of American exceptionalism not only raises the risk of war in places where he advocates pre-emptive intervention like Iran or North Korea, it is also a threat to the entire international system that men like Scowcroft worked hard to shape and strengthen.

Scowcroft’s temperament was famously even-keeled. He did not seek the spotlight. He worked behind the scenes but never let his ego get in the way. This enabled him to maintain good relations with other colleagues and to provide quiet counsel to the president. Bolton is a bomb-thrower, combative, historically nasty to his subordinates. He also has a taste for the spotlight (coming as he does in the wave of cable-television personalities hired into this administration.) Worse, his confrontational, hot-headed persona is likely to exacerbate the worst traits of his boss, the president.

Scowcroft was famously disciplined, waking very early each morning to work out before heading to the office, demanding adherence to a strict policy process that ensured all views would be heard, carefully considered and then framed thoughtfully before being presented to the president. Bolton has a reputation as a loner who does not play well with others. He is an effective bureaucratic in-fighter and has a record of advancing his views. While these are useful traits, they are not most important in a job that has among its key roles and responsibilities serving as an honest broker among other actors and agencies.

Because Scowcroft was seen as respectful of the process and his colleagues, he was trusted to represent their views fairly to the president. To say that Bolton was not similarly trusted by his colleagues in the State Department when he was at the U.N. is an understatement.

Because Scowcroft saw his job as managing a process rather than advancing his own views or profile, he was able to work across agencies harvesting the best support for White House decisions and, importantly, ensuring effective implementation of those decisions. Bolton’s contrary impulses in these areas will make it harder for him to effectively develop or implement policy.

The biggest problem with Bolton however, is not Bolton. It is Trump. national security advisers are just as powerful as the president lets them be. If the president respects process, seeks good advice, demands his adviser presents him with real choices, empowers that adviser by requiring all work through a process, success like Scowcroft’s is possible. Scowcroft also achieved it because he and, for example, George H.W. Bush were very close friends who had a deep bond of trust and mutual respect. But Trump has shown utter disregard for process and for outside advice. He is profoundly undisciplined and influenced more by television, family and friends than his Cabinet.

What’s even worse is that he does not want Bolton to provide advice. He seemingly wants him to validate, promote, and defend Trump’s decisions. In keeping with Trump’s Fox News centric view of the world, he sees advisers only to the degree they appear on the news and weighs their performance by the degree to which they make him look good.

Thus, even were Bolton suited to the job to which he has just been appointed, he would fail because of his boss. But alarmingly, Bolton seems likely to exacerbate Trump’s worst impulses while failing to offer him the counsel he desperately needs.

In other jobs, this could mean policy misfires or inaction of limited consequence. But when it comes to the job of national security adviser the stakes are much higher. The selection of Bolton and Trump’s predispositions now make war and the undermining of much of what America has sought to build for three generations ever more likely.