That red line, as Mr. Obama has sternly asserted time and again, is the use of chemical weapons by the regime of Syrian President Bashar al-Assad.
“You cross that line, mister, you are grounded,” Mr. Stewart warned an imaginary President Assad.
Flash to footage of Defense Secretary Chuck Hagel confirming, "with some degree of varying confidence," that the Assad regime has used chemical weapons.
And back to Stewart, gleefully awaiting the fire and brimstone about to rain down on Assad.
“We don’t know how they were used, when they were used, who used them,” Obama said Tuesday in a press conference, walking back his threatening stance.
This line so tickled Stewart, he went Seussical.
“Did he use them in a boat? Did he use them with a goat? Did he use them in a house? Did he use them with a mouse?” (From Obama’s new book, “Red Lines and Gas,” if you’re interested.)
The new red line, it seems, has shifted. (We hope Obama’s using erasable ink.)
Spooked perhaps by the specter of the Iraq war, the US says it now has to present hard evidence of chemical weapons use to the UN. Notably, it needs to persuade Russia that the Assad regime used deadly sarin gas against its own people.
“So intervention in Syria relies on us convincing Vladimir Putin that it’s bad to poison people?” a dubious Stewart asked.
In fact, Obama’s reluctance to engage Assad is no surprise.
For starters, polls show Americans just don’t care about Syria, with fewer than 1 in 5 respondents telling the Pew Research Center that they are following the situation in Syria closely. (If you’re still reading this, congratulations! You’re in the minority.)
According to a recent CBS/New York Times poll, 62 percent of the American public say the US has no responsibility to take action in Syria.
That reluctance to intervene is a byproduct of the 10-year war in Iraq, an exercise few Americans are eager to repeat.
That war’s controversial beginnings (remember WMDs and talk of mushroom clouds?) and exceptionally challenging mission have resulted in a sort of war weariness among not only the public, but American leadership, as well.
Hence Obama’s shifting red line, of which North Korean leader Kim Jong-un has, no doubt, taken note.
He’s not the only one. If Obama’s weak ultimatum on Syria is any indication, we bet Sasha and Malia are not too worried about Obama's tattoo threat, either.
They have enjoyed some unauthorized West Wing pranking, scot-free.