U.S. President Donald Trump vowed on Monday to do everything he can to make Syria successful after landmark talks with Syrian President Ahmed al-Sharaa, a former al Qaeda commander who until recently was sanctioned by Washington as a foreign terrorist. Sharaa's visit capped a stunning year for the rebel-turned-ruler who toppled longtime autocratic leader Bashar al-Assad and has since travelled the world trying to depict himself as a moderate leader who wants to unify his war-ravaged nation and end its decades of international isolation.