In a statement released after the death of the bill, Herpin said he was "extremely disappointed" by its failure.
"It’s important that we preserve and strengthen freedom of the press so that the press can act as watchdogs of government on our behalf," said Herpin.
Herpin was inspired by the case of Fox News reporter Jana Winter. Lawyers in the Aurora theater shooting case tried to make Winter divulge the sources for one of her stories. But she successfully fought that effort using New York state’s shield law. That law became the model for Herpin's bill.
Currently under Colorado law, a lawyer who wants to force a reporter to testify has to establish three things: that the information is relevant to the legal proceeding; that it cannot be obtained by any other means; and that their interest in revealing the information outweighs the first amendment right of a free press. Herpin's proposal would have tightened those criteria and allowed reporters to keep secret any information they obtained "in confidence."
The media shield bill died on a party line vote, with Democrats opposing. Opponents argued that Colorado law already offers sufficient protection to journalists.
[The Associated Press contributed to this report]