In a 5-to-4 ruling, the top court upheld the regulator's 2004 decision to hold broadcasters liable for the occasional expletive.
A case the justices heard Tuesday offers them an opportunity to decide the standard for proving illegal discrimination.
Reformers push to limit what is protected.
The decision in the Al-Marri case means the president still has the power to hold 'enemy combatants' indefinitely without charge.
The White House is seeking to protect at least some of its Bush-era privileges.
An Eritrean who worked at a prison where torture occurred gets another chance to live in America.
The move places the last remaining "enemy combatant" in the US before a civilian court instead of a military tribunal.
He ordered the case of enemy combatant Ali Al-Marri, who has been held in solitary confinement for five years without charges, to be moved to the US criminal justice system.
Lawyers for the Summum religion had argued that its monument should be allowed in a public park where the Ten Commandments were already displayed.