A significant moment for Ukraine - as the US falls into line with NATO. 

President Donald Trump's pledged billions of dollars of weapons to Ukraine, through a sale to NATO. 

He's also threatening Russia with 100 percent secondary tariffs if the Kremlin doesn't make a ceasefire deal within 50 days. 

Former Australian ambassador to Russia, Peter Tesch says US policy is too fickle to make this a complete game changer.

"It is an important signal - and a very welcome signal to Ukraine and NATO that the US won't hinder their efforts to defend Ukraine at their own expense."

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