Gov. Rick Perry has made Texas the 37th state to pass a shield law by signing the Free Flow of Information Act, which went into effect Wednesday. Check out how the Texas rules compare to other states' by viewing this interactive map produced by the Austin American-Statesman.

By signing the shield law, Perry is giving protection to Texas journalists and their sources, and by extension helping journalists do their job for the public.

Janet Elliott from the Houston Chronicle writes:

Journalists have argued that a shield law is needed to protect whistle-blowers who might be reluctant to discuss government and private industry abuses if they knew their identity would be revealed.

The law may protect reporters and their sources in some cases -- but not all.

Dave McNeely writes in The Tribune:

The compromise that caused the prosecutors to drop their opposition to the bill is that reporters would not be protected from revealing their sources if they were aware the source had committed a felony and efforts to obtain the information through other means had proved fruitless, or if the identity of the source is reasonably necessary to stop or prevent reasonably certain death or substantial bodily harm.

Opposition from the Texas District County Attorneys Association killed the law in the past two legislative sessions, according to McNeely.

The bill, authored by Rep. Trey Martinez Fischer, D-San Antonio, will take effect immediately.