There was a time when all three major television networks broadcast the Republican and Democratic national conventions "gavel to gavel." No longer. In more recent years, they've reduced their coverage to one hour per night. And now, it appears, NBC won't present any coverage at all of the Democratic convention on Wednesday, Sept. 5. That's the day of the NFL season kickoff (New York Giants vs Dallas Cowboys). Such NFL season kickoffs ordinarily are presented on Thursday, but the NFL agreed to move the game to Wednesday this year so that it would not conflict with President Obama's acceptance speech scheduled for Thursday. CBS and ABC (and NBC's sibling MSNBC), of course plan to cover the convention on Wednesday, a day that will feature an address by former President Bill Clinton.