He wrote this in his article for The New York Times, the press service of the head of state reported on Friday.
"Despite Kremlin propaganda, Mr. Putin is weaker than he would have the West believe. The West can - by raising the cost of his aggression - force him to fall back into line. How much more hostility will it take before the West's words of concern graduate into the hard currency in which the Kremlin trades - strength? Russia has deployed chemical weapons in Britain; undertaken cyberattacks and hacking attempts across the West; bombed civilians in Syria; fomented a war in Eastern Ukraine that has caused more than 10,000 Ukrainian deaths; and spread disinformation to confuse, anger and frighten citizens around the world. Is now not the time to act?" Poroshenko said.
According to him, Russia wants to return to an era where property and land are seized by force.
"It starts with Ukraine and continues westward as far as the democratic world will allow. Democratic countries must now make a choice: Stand up for what is right or continue appeasing President Vladimir Putin. If history has taught us anything, it is that appeasement has deadly costs," Poroshenko wrote.
He recalled that U.S. President Donald Trump showed true leadership by canceling his meeting with Putin at the G20 summit in Argentina over Russia's seizing of Ukrainian ships and sailors.
"We have enjoyed tangible support from the White House and Congress, including defensive weapons, stronger sanctions and more secure American energy supplies. Together, partners on both sides of the Atlantic can continue to raise the cost to Russia for threatening our collective security," he said.
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