The threats, pressure and ultimatums have come and gone, but Russian President Vladimir Putin has maintained Moscow’s uncompromising demands in Ukraine, raising fears he could use a planned summit with U.

For President Vladimir V. Putin of Russia, it is an opportunity not just to end the Ukraine war on his terms, but to split apart the Western security alliance.

NATO Secretary General Mark Rutte said Friday’s summit between President Donald Trump and Russian President Vladimir Putin in Alaska will be an important test in ending the war in Ukraine.