This is part of our 2015 elections coverage. Get more results here.

Voters in Washington state on Tuesday opted to increase penalties for selling, purchasing or trading certain animals threatened with extinction. Seventy-one percent of voters approved the initiative.

Supporters say the law will be an important step to reduce poaching of elephants and other endangered species. But critics say it will unfairly punish people who sell ivory and other animal parts that come into the United States legally.

People caught trafficking certain endangered species (elephants, rhinos, lions, tigers, leopards, cheetahs, marine turtles, pangolins, sharks and rays) will now face up to five years in prison and a $10,000 fine.

Microsoft co-founder Paul Allen bankrolled the signature-collecting effort. Besides Allen, the initiative had the backing of the Seattle-based Woodland Park Zoo, the Seattle Aquarium and the Humane Society of the United States. Its most vocal opponent was the National Rifle Association.

So far, only three states (California, New York and New Jersey) have bans on ivory sales, but lawmakers have introduced similar bills in more than 20 states. This year in Washington state, legislation to regulate elephant and rhinoceros horns stalled in committee.

"We cannot let our home state be an accomplice to the extinction of these majestic animals," wrote Fred Koontz, the vice president of field conservation at Woodland Park Zoo, in an op-ed for the Seattle-based website Crosscut. "A measure passed by popular vote will send a clear message nationally and internationally that we must do our part to save these animals from extinction."

The ballot measure's success came as a surprise to no one. In an October poll, about 66 percent of registered voters favored the initiative. Leading up to the election, supporters raised more than $3.4 million -- about 40 percent of which came from Allen, but venture capitalist Nick Hanaeur, software engineer Paul Maritz and philanthropist Jeannie Nordstrom also contributed a combined $450,000.

This is part of our 2015 elections coverage. Get more results here.