"The Supreme Court rejected the argument that this was a compensable taking under the Takings Clause," O'Shea said.
The 10th Circuit suggested that, similarly to the free-speech-facilitating state law in Pruneyard, the Oklahoma law might be viewed as intended to expand or secure the individual right to bear arms for self-protection, O'Shea said.
The Second Amendment is not generally implicated by employer policies, O'Shea said, because like other provisions of the Bill of Rights, it only restricts government action, not action by private entities. Â However, he said states can confer rights through state constitutional provisions or through legislation that go beyond the federal right, as in Pruneyard. O'Shea said he thinks that is what the court meant when it said one rational basis for the Oklahoma laws could be to expand or secure the right to bear arms.
The 10th Circuit panel also concurred with the district court that the Oklahoma law does not violate due process.
O'Shea said a few states have experimented with laws like Oklahoma's, permitting employees to store lawfully owned firearms in their locked cars at work, from the perspective that they secure their ability to carry firearms for protection while commuting to and from work.
He said a Florida federal district court largely rejected an OSHA pre-emption challenge to a similar law in that state, in Florida Retail Federation Inc. v. Attorney General of Florida.
Attorney General Drew Edmondson's office represented the state in seeking to have the Oklahoma law upheld.
"It was our opinion that the law is constitutional, and the court agreed with us," spokesman Charlie Price said.
O'Shea said he found it interesting that the state turned oral argument in defense of the law over to Charles Cooper, a Washington, D.C., attorney who filed an amicus brief on behalf of the National Rifle Association. He said Cooper was designated as a special assistant attorney general in the case.
O'Shea said the Cooper and Kirk law firm handles a lot of high-powered, often politically charged litigation in federal court.
ConocoPhillips was a key plaintiff in the case.
Spokesman Rich Johnson said the company is disappointed with the 10th Circuit ruling, but has not had time to determine how it will proceed.
"The safety of our employees is a top priority of ConocoPhillips," he said.
The Associated Press contributed to this story.