In the quarter-century that Vladimir Putin has been in power, Kremlinologists have come to know his political and bureaucratic style down to the smallest details. There is no intrigue left in any of his political decisions, much less in his rhetoric or personnel policy.

So when Dmitry Kozak resigned as deputy chief of Putin’s administration, many were quick to speculate on the reasons and the implications for his doing so. This news would hardly have been widely discussed were it not for the rumor that Kozak disapproved of the 2022 invasion of Ukraine.

To understand Kozak’s current standing, one needs to look at Putin’s personnel landscape.

Kozak was one of the most capable managers of the first 15 years of Putin’s rule. Trusted as a fixer rather than a public politician, he cycled through the most powerful back-office jobs: head of the government apparatus (cabinet staff), senior roles in the presidential administration and special assignments that required Putin’s direct oversight.

From those perches, Putin sent him to end the Second Chechen War as envoy to the Southern Federal District; to shepherd preparations for the Sochi Olympics; to help manage the 2014 annexation of Crimea; and to represent Moscow in the Normandy Format talks on the war in Donbas.

In a system where few survive long at the top of the bureaucracy, Kozak lasted for two decades and earned a reputation as the administration’s “Iron Chancellor.”

Those who failed at their assignments retired quietly and with honor, like Vladimir Yakunin, or were given big state corporations, like Vitaly Mutko. Those who were incompetent or unstable but craved publicity, like Dmitiry Mironov or Medvedev, were given free rein to become court jesters , though both had once had grand prospects (one as Federation Council chair, the other as president and prime minister).