It was a year ago, almost to the day, that President Barack Obama warned the Syrian dictator, Bashar al-Assad, not to deploy chemical weapons in his fight to stay in power. “We have been very clear to the Assad regime, but also to other players on the ground, that a red line for us is we start seeing a whole bunch of chemical weapons moving around or being utilized. That would change my calculus,” Obama said. “That would change my equation." He went on: "We’re monitoring that situation very carefully. We have put together a range of contingency plans.” Earlier, the president had said that Assad would be “held accountable by the international community” if he made the “tragic mistake” of using these weapons.

As we know now, Assad did use these weapons, on repeated occasions, in small-scale attacks. The administration’s response to these confirmed reports of chemical weapons use came in June, when it authorized the transfer of small arms to the rebels, small arms the administration acknowledged would not tip the rebellion toward success.

There was one other international response to the use of these chemical weapons: After much delay, the United Nations sent a team of chemical weapons investigators to Syria this week. That team is, right now, not far from the Ghouta region east of Damascus, where, overnight, the Syrian regime is alleged to have launched its largest chemical weapons attack to date. The number of dead -- mostly civilians, including many children according to the reports we have -- stands anywhere from several dozen to more than a thousand. The videos of the attack aftermath, now being posted on YouTube at a rapid clip, are absolutely horrendous.

Two questions are raised by reports of this attack. The first, of course, is whether it happened the way Syrian rebels said it happened. That is why immediately dispatching the UN team, already in-country, to the affected areas is so vital. If this process worked the way it should, they would be there already. If the Syrian regime denies the UN inspectors permission to visit these areas, well, that is kind of an answer in itself.

The second question is, why would the Assad regime launch its biggest chemical attack on rebels and civilians precisely at the moment when a UN inspection team was parked in Damascus? The answer to that question is easy: Because Assad believes that no one -- not the UN, not President Obama, not other Western powers, not the Arab League -- will do a damn thing to stop him.

There is a good chance he is correct.

(Jeffrey Goldberg is a Bloomberg View columnist. Follow him on Twitter.)