He's denying that he said the red line was ours when he clearly said "...a red line for us...""
Now he is backpedaling saying that the red line is the world's red line so he either now speaks for the entire world or he is lying again.
Which of the two seems more likely?
Moving goalposts?
Yeah..it is a red line for the United States, and the world.
The 1925 Geneva Convention prohibits the use of Chemical Weapons in warfare.
The World, including the United States signed on to that.
Unfortunately Ronald "The Traitor" Reagan broke with that convention when he backed the use of Chemical Weapons by Iraq against Iran, and again by Iraq against it's own people.
What Obama said was the use of Chemical Weapon would change his, The President of the United States, "calculus" in how to deal with a very fluid and ongoing issue.
That might include force. That might include reminding the world of it's almost 100 year old obligation to make sure these weapons are never used.