Montana ? Two decades after the federal government spent a half-million dollars to study the reintroduction of gray wolves to the Northern Rockies, lawmakers say it’s time for Congress to step in again — this time to clamp down on the endangered animals.

To do so they are proposing to bypass the Endangered Species Act and lift protections, first enacted in 1974, for today’s booming wolf population. Critics say the move would undercut one of the nation’s premier environmental laws and allow for the unchecked killing of wolves across the West.

But bitterness against the iconic predator is flaring as livestock killings increase and some big game herds dwindle.

And with state efforts to knock back the predators’ expansion stalled in court, senators from Montana, Wyoming, Idaho and Utah want to strip wolves of their endangered status by force.