Like his predecessor a decade ago, a Missoula federal judge is now trying to decide whether the U.S. Fish and Wildlife Service jumped the gun by delisting Yellowstone grizzly bears.

During a hearing Thursday, U.S. District Court Judge Dana Christensen said he had already waded through the history of grizzly bear protection and minute details of federal laws and agency rules. He had some preliminary opinions, but he wanted attorneys to focus on aspects that were most critical to their arguments to help him make his final decision.

“It has been brought to my attention that there may be an expectation that I might rule from the bench today. At the risk of disappointing you, that is not going to happen,” Christensen told the court. “If I was to issue a decision today, that would mean that I’ve already made up my mind.”

With that, he gave an hour each to the plaintiffs – those opposed to delisting under the current circumstances – and defendants – the U.S. Fish and Wildlife Service – to present their best arguments.

In 1975, the USFWS declared that grizzly bears in the lower 48 states qualified as threatened – the species was dwindling and might become extinct without help - under the 1973 Endangered Species Act. That law, related amendments and subsequent court decisions are the only aspects a federal judge considers, although attorneys on both sides wandered into more emotional or societal reasons for why Christensen should rule in their favor.

The plaintiffs argued that while isolated bear populations have since improved, namely the greater Yellowstone population, grizzly bears in six regions are still struggling overall. Therefore they should remain protected until all populations have recovered.

But last summer, the USFWS removed grizzlies in the Yellowstone region from protection, declaring it to be a distinct population. That determination sparked many of Thursday’s arguments.

The government first identified the populations as separate entities in its 1993 Grizzly Bear Recovery Plan. Then in 1996, the USFWS created the Distinct Population Segment policy with the intent of protecting isolated populations of an unlisted species that were in danger of extinction.

Since then, the USFWS has used the policy for the opposite reason, with varying success.

Most recently, the U.S. Humane Society won a lawsuit a year ago challenging a USFWS decision to delist wolves in Michigan, Wisconsin and Minnesota as a distinct population while wolves in other parts of the country remained protected. A D.C. appellate court said the USFWS hadn’t evaluated how taking those wolves out of the equation would affect the remaining population.

On Thursday, the plaintiffs said the USFWS was making the same mistake with grizzly bears.

“If the Service insists that the original rule, related to the lower-48 states, was never reopened and remains in effect, this rule must be complied with,” said WildEarth Guardians attorney Matthew Bishop. “It includes no provision for piecemeal delisting.”

EarthJustice attorney Tim Preso said by carving out the Yellowstone population, the USFWS hadn’t looked at how that would legally effect the rest of the bears. The grizzly recovery plan intended to reintroduce bears in the Bitterroot and northern Cascade mountains. Preso said if the Yellowstone population remains delisted, the rest of the grizzly population in the lower 48 states would be divided into distinct segments. Since the law requires that populations exist already, those two regions would disappear because they have no bears.

“They have set up a situation where anyone who opposes listing in the Cabinet-Yaak or the Bitterroot can now file a petition that says, ‘You have an unlistable entity.’ And we see these cases where they say you have to delist,” Preso said. “The D.C. court said, “You have to consider all relevant factors and you blew it off.’”

USFWS attorney Coby Howell insisted that wouldn’t happen because the USFWS kept the rest of the population listed as threatened. Howell said the USFWS did that because re-evaluating the remaining population outside Yellowstone would be too difficult.

Christensen pressed Howell on that assertion, questioning whether the USFWS did enough by just leaving the threatened listing in place. Christensen also pointed out that a main consideration of the recovery plan was connectivity between populations to make sure inbreeding didn’t occur.

“When we create a (distinct population) in one ecosystem without considering the impact on other ecosystems, we’re running afoul of the intent as it relates to the original grizzly bear listing decision,” Christensen said.

As the hearing wrapped up, Preso told the judge the plaintiffs would request a temporary stop on the Wyoming hunt if Christensen couldn’t decide before Saturday.

Christensen said he understood that time was of the essence and he would give the matter his full attention after he had heard attorneys’ arguments.