• Putin

  Take Putin. He started off as something of a reformer who stabilized post-Yeltsin Russia and oversaw an economic boom, thanks to rising oil prices.

  His invading Ukraine to restore a mythical Russian Motherland was inevitable.

• Xi

  It has made China more closed than any time since the days of Mao — complete with the sudden disappearances of the ministers of defense and foreign affairs — and sparking talk that we may have already seen “peak China” in terms of the country’s economic potential, which would be an earthquake for the global economy.

  Xi Takes Flurry of Small Steps to Open China After US Trip

  China has unleashed a flurry of market access concessions in the wake of last month's leaders' summit. Beijing approved a long-delayed Mastercard Inc. joint venture, then followed up by green lighting one of the world's largest technology mergers between US chipmaker Broadcom Inc. and cloud company VMWare Inc. Last week, officials announced visa-free access to China for six countries.

  

• 'Old Donald'

  Needless to say, watching 'Old Donald''s effort to overturn our 2020 election by inspiring a mob to ransack the Capitol on Jan. 6, 2021, and then seeing this same man become the leading Republican candidate for president in 2024, makes our next election among our most important ever - so that it won't be our last ever. That was not the plan.

• Netanyahu

  'He began with a worldview that said, 'I'm the best leader for Israel at this time.' Slowly it morphed into a worldview that said, 'The worst thing that can happen to Israel is if I stop leading it, and therefore my survival justifies anything.'

  After Netanyahu Rejects a Truce Proposal, Hamas and Israel Signal They May Keep Talking

But there are also important differences among the four. Netanyahu and 'Old Donald' are facing pushback in their democracies, where voters may yet oust or stop both of them — and neither has started a war. Xi is an autocrat, but he does have an agenda to improve the lives of his people and a plan to dominate the major industries of the 21st century, from biotech to artificial intelligence. But his increasingly iron-fisted rule may be exactly what prevents China from getting there, chiefly because it's sparking a brain drain.

Putin is nothing but a mafia boss masquerading as a president. He will be remembered for transforming Russia from a scientific powerhouse - which put the first satellite into orbit in 1957 - into a country that can't manufacture a car, a watch or a toaster that anyone outside of Russia would buy. Putin had to dial 1-800-NorthKorea to scrounge for aid for his ravaged army in Ukraine.

'Old Donald', ultimately, is the most dangerous of the four - for one simple reason: When the world becomes this chaotic, and such key countries go off the plan, the rest of the world depends on the United States to take the lead in containing the trouble and opposing the troublemakers.