"Today's chemical attack in Syria against innocent people including women and children is reprehensible and cannot be ignored by the civilized world," Spicer told reporters. "These heinous actions by the Bashar al-Assad regime are a consequence of the past administration's weakness and irresolution." Spicer also said: "President Obama said in 2012 he would establish a red line against the use of chemical weapons and then did nothing. The United States stands with our allies across the globe to condemn this intolerable act." (Later in the day, the White House issued a statement echoing Spicer's remarks.)
It will come as no surprise at this point that the Trump White House's position was hypocritical. First, Obama's red line at the time was a threat of US military action against Syria should it continue to use chemical weapons. When Obama asked the GOP-led Congress to authorize the potential use of force against Syria, the Republicans, not wanting to take a firm stance, declined to hold a vote. Still, Obama's move prompted Assad to agree to a Russian-brokered deal to give up his chemical weapons. To a degree, Obama's threat worked.
Whether or not Obama's policy in 2013 was successful, this much is clear: at that point, Trump had an unambiguous position regarding Syria— do nothing. Throughout this episode, Trump tweeted up a storm about Syria. Repeatedly, he declared—occasionally in all-caps! - that Obama should not be messing around in Syria. He said there was no reason to attack Syria or take any action there. Let the Arab League deal with the problem. He was asserting that Obama should not respond to the chemical attacks - a policy certainly in sync with Assad (and his Russian patrons). Stay out of this, Trump demanded, and focus on domestic issues.
Here is a sample of Trump's 2013 tweets on the subject: