What is the FCC equal time rule at center of Talarico interview?

The Federal Communications Commission is aggressively enforcing its new guidance on a so-called equal-time statute, pursuant to a 20th-century federal law that requires broadcast television networks to offer opposing candidates running for the same office the opportunity to speak on-air.

The latest television program affected by the policy is The Late Show with Stephen Colbert, whose host interviewed Texas Democratic state Rep. James Talarico in a YouTube video rather than on the usual broadcast. CBS lawyers advised Stephen Colbert to take the interview off the air, but he posted the conversation on YouTube anyway.