Newsweek published an article titled "Now Mattis Admits There Was No Evidence Assad Used Poison Gas On His People" at the beginning of this month. The opinion piece by reporter Ian Wilkie called the supposed admission by James Mattis "striking."
Wilkie linked to an Associated Press article in which a reporter named Robert Burns makes a similar claim.
Wilkie rightly pointed out that a flip-flop by Mattis on the point would be very significant. This is because the claim about Assad's alleged vile act was used in a White House (NSC) memorandum which the administration produced and declassified (made available to the public) in order to justify an American Tomahawk missile strike against Syria's Shayrat airbase.
In other words -- according to Newsweek -- Mattis appeared to admit that there was no real justification for the American attack on Syria. The memorandum that the government scrambled to put together to justify the attack was based on a pile of lies and/or errors, according to the report.
"Secretary Mattis has added fuel to WMD propaganda doubters' fire by retroactively calling into question the rationale for an American cruise missile strike."
A copy of the Mattis statement, including his confusing comments about Assad's use of poison gas, has been circulating on social media.
It is claimed that Mattis did say that Assad used poison gas in 2013 and 2017.
In addition to that allegedly clear statement, Mattis also made a confusing comment full of sudden break-offs, where the secretary of defense would stop talking mid-sentence and take up another train of thought in a way that made his point difficult to discern.
It was those latter, vague remarks that Ian Wilkie seized upon when he wrote his Newsweek piece.