The dwindling polar bear population has been impacted pretty severely in recent years by climate change and overhunting. The Polar Bear Specialist Group has listed most regional populations as declining with a very high risk of continuing decline. Russia has taken heed and banned its already slim hunting quota, meaning that it would be illegal to kill a single bear.
Why is the US still allowing it?
"A Russian-U.S. commission last year agreed to restrict polar bear hunting to 29 animals per year for each country. But The Polar Bear program, established under Putin's patronage, said this week that Russia had waived its quota for bear hunting.
"Although the polar bear is an endangered animal, officials in Russia and the U.S. have said hunting is vital for the indigenous people in Alaska and in far-eastern Russia across the Bering Strait.
"The Polar Bear program, which said U.S. officials had long been reluctant to introduce the cap on hunting, said around 100 polar bears a year have been killed in Alaska in recent years."
Because I would hate to take away an American's right to kill an endangered animal from a helicopter.