BEIJING — He has stifled his political opponents and enriched friends and cronies. He annexed a chunk of Ukraine, threw moral and military support to Syria’s dictator in a brutal civil war and tried to tip the scales in an American presidential election. For the second time in barely a decade, he stands accused of orchestrating the exotic poisoning of an exiled former intelligence operative in Britain.

So what is it exactly that has made Vladimir V. Putin a hero for the world’s populists, strongmen and others occupying the fringes of global politics, both left and right?

The answer, probably, is all of the above.

For more than 18 years in power, Mr. Putin has managed to defy his critics at home and abroad by ignoring the norms and institutions of the global order that emerged after the collapse of the Soviet Union. Where once he seemed out of step with the liberalizing West, he now seems to be the vanguard of a new generation of leaders — in Turkey, Hungary, Italy and even America — who are challenging it.

He offers no coherent or comprehensive ideology, as Communism once did, but rather an amorphous model for protecting national sovereignty against international organizations, like the European Court of Human Rights, that were created to stifle ugly manifestations of ethno-nationalism.