The latest rift with President Volodymyr Zelensky of Ukraine serves as a reminder that President Trump readily lashes out at other world leaders, only to grow outraged if they fight back.

After Russia released an American prisoner, President Trump’s special envoy praised President Vladimir V. Putin as “a humanitarian.” Our White House and national security correspondent, David E. Sanger, describes how the release comes amid Mr. Trump’s broader shift toward Russia and away from Ukraine.

Mr. Hubbard, a 74-year-old teacher, was held for more than four years on what the State Department called fabricated charges.

The move buys good will with President Trump while costing the President Vladimir V. Putin — who is wanted for war crimes — little.