Bush's diplomatic pressure forced Saddam's suppliers and allies to push him to remove the WMDs for safe keeping and to hide them from International inspectors. Bush basically told Saddam's allies and enablers that if US forces were attacked by WMDs he would consider it an act of war by the country that originally supplied the Iraqis with the weapons and technology and that the United States would respond in kind.
Saddam had outsourced some of his WMD efforts to Syria and funded them with off the books oil for food money to avoid the Inspectors and much of his WMD stockpiles went there in the run up to the Iraq war.
Assad is now threatening to use those weapons if he is about to lose the Syrian civil war and there is also Assad's implicit threat to expose the details of the WMD transfers from Iraq and the fact that Congressional Democrats, not the least of whom is Joe Biden, knew full well that Saddam really did have WMDs and they were all moved out before the war because of George Bush's “cowboy” pressure on the countries supplying Saddam with WMDs. Because of this, no WMDs were used against US and coalition troops during the Iraq war because they long gone.
This did not stop the Democrats and their media allies from cynically lying about the Iraqi WMDs and attacking the Bush Administration with the whole “Bush lied, people died” BS story.
Assad no doubt has the evidence to to document the whole back story on the WMD exodus from Iraq and proof that these same Democrats had full knowledge of the transfers and then lied to the American people about Saddams’ WMDs for personal political gain to the great detriment of America's Foreign Policy standing in the world.
Unlike all other Arab states in the “ Arab Spring”, Obama has actively supported Assad or at the very worst remained neutral in the Syrian civil war.
It's possible that the reason for this is that Assad has been blackmailing Obama with treats to expose the WMD scam and expose the lies of the Democrats and the media.
We may be in the end game of this because it seems that the truth about the WMDs is beginning to be leaked out by our government before either the truth comes out or the weapons are used either by Syria or terrorists. Of course, it will all be Bush's fault.