It remains to be seen just how lasting and severe President Donald Trump’s turn against Vladimir Putin will be. Trump has criticized the Russian president in unprecedented terms in recent days and signaled he’ll send vital weapons to Ukraine.

But his frustration with Putin has grown. Last week, the president said the United States was taking “a lot of bullshit” from Putin. Today, he authorized a significant shipment of U.S. defensive weapons to Ukraine via NATO and threatened Russia with new tariffs if the war does not end in 50 days.

“Putin will not negotiate as a loser,” one of his longtime associates tells TIME by phone from Moscow. “He knows that winners don’t get punished, and if he wins, all of this” — the sanctions, the tariffs — “will go away.”

Trump's threat against Russia runs parallel to a Senate-led effort to pass crippling sanctions on countries that buy Russian energy.

Vladimir Putin’s conduct has prompted Donald Trump’s shift as Russia’s war effort in Ukraine has gotten only more aggressive.

President Trump reveals how Russian leader 'talks nice, then bombs everybody' as the U.S. prepares to send Ukraine Patriot missiles under a NATO agreement.

President Trump is hosting NATO Secretary General Mark Rutte at the White House on Monday as the U.S. agrees to sell new and more weapons to Europe and Ukraine.