(Bloomberg) -- Chubb Ltd. Chief Executive Officer EvanGreenberg said the U.S. must avoid the risk of becoming soinward-looking that the nation cedes its historic role in shaping aliberal order that has benefited the country for decades.

“Without U.S. leadership, the system lacks confidence and ourallies and others seek alternatives,” Greenberg wrote in his annual letter, which waspublished on the company’s website. “If we don’t defend this worldorder, and if we allow our current populism to turn intoprotectionism and simply follow a narrow view of an America Firstpolicy, other countries will naturally follow suit with their ownbrand of nationalism.”

'Cautiously optimistic'

Greenberg didn’t mention President Donald Trump by name in theletter. While the CEO said he’s "cautiously optimistic" about manyof the administration’s economic policies, "particularly aroundderegulation for business, tax reform, and infrastructure andmilitary spending," the CEO stressed the importance of close tieswith Mexico, a nation where he has expanded through acquisitions.And Greenberg criticized Russia’s Vladimir Putin, a leader who haswon praise until recently from Trump.

“A stable, growing, prosperous and open Mexico, friendly to theU.S., is in our national interest,” Greenberg wrote. “Russia is notour friend and no one should misunderstand them. Russia and Putinwant to reassert their influence — they do not respectnation-state borders, physical or cyber, and they have a desire toundermine democratic states.”

‘Set the tone’

Greenberg, 62, built one of the world’s largest insurers last yearby combining his Ace Ltd. with Chubb Corp. TheZurich-based company operates in more than 50 nations. He has beenvocal on the benefits of globalization, saying in February that theU.S. needs to remain open to people from the rest of the world.Those remarks followed an order by Trump to limit travel to theU.S. from some Muslim-majority countries. The letter built onGreenberg’s warnings.

“We have to have our eyes open to the fact that we could bewitnessing the initial stages of the unraveling of the democraticliberal world order we have known all our lives, and that wouldspell trouble for our country,” Greenberg wrote. “We should nottake the world we grew up with for granted. America should continueto set the tone and pace — we are the leaders of the free world andit relies on our dependability.”

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