On a recent brisk day at Yellowstone National Park, dozens of people lined up with their viewing scopes to get a glimpse at one of the main attractions of the reserve: gray wolves. Twenty-five years after wolves were reintroduced to Yellowstone National Park the animal still holds people's fascination. It started with a few dozen wolves brought in crates from Canada to Yellowstone and central Idaho. Others wandered down into northwest Montana. Thriving on big game herds, the population boomed to more than 300 packs comprising some 2,000 wolves, occupying territory that touches six states and stretches from the edge of the Great Plains to the forests of the Pacific Northwest. Now the 2020 election offers an opportunity to jumpstart the wolf's expansion southward into the heart of the Rocky Mountains. A Colorado ballot initiative would reintroduce wolves on the state's Western Slope. The effort, if successful, could fill a significant gap in the species' historical range, creating a bridge between the Northern Rockies gray wolves and struggling Mexican gray wolf packs in Arizona and New Mexico. Yet the prospect of wolves is riling Colorado livestock producers, who see the predators as a threat their forebears vanquished once from the high elevation forests where cattle graze public lands. Hunters worry they'll decimate herds of elk and deer. It's a replay of animosity that broke out a quarter-century ago when federal wildlife officials released the first wolves into Yellowstone. The species had been annihilated across most of the contiguous U.S. in the early 1900s by government-sponsored poisoning, trapping and bounty hunting. Even with protections under the Endangered Species Act, thousands of wolves were shot over the past two decades for preying on livestock and, more recently, by hunters.