Note to President Obama: When friendly--darn near worshipping--networks like CBS turn on you, then you know that you've crossed into dark, dark waters.
Still, the Obama administration's attempt to exclude FoxNews from interviews and such is not anywhere near the worst Presidential assault on the media.
In the late 1790s, Alexander Hamilton's Federalist Party drafted the Sedition Act, and John Adams signed it into law. The Sedition Act gave the executive powers to prosecute anyone who dared to "write, print, utter, or publish" criticisms of the President (Adams was a Federalist) or Congress (controlled by Federalists). The law allowed for punishments of fines up to $2000 and two years imprisonment.
The Federalists intended the Sedition Act to silence the growing opposition of Thomas Jefferson's opposition party. Instead, it made a lot of people take a long, hard look at the Federalists. Jefferson's party accused Federalists of being tyrannical and monarchical in disposition. The Sedition Act all but proved this.
During the Civil War, the Lincoln Administration had many critical newspapers shut down, presses destroyed, and and newspapermen imprisoned. Of course, that's nothing compared to what he did to those who would decline consent to his government.
No abuse of power that Obama has thus far committed is without precedent. It is kind of funny that while the administration has been ignoring the Constitution right and left, it's not until it crossed the freedom of the press that the big media outlets (excepting FoxNews, of course) cried foul.