WASHINGTON — A plan announced over the weekend for getting the bulk of Syria ’s chemical weapons out of the country in coming weeks has raised major concerns in Washington, because it involves transporting the weapons over roads that are battlegrounds in the country’s civil war and loading them onto a ship that has no place to go. Security for the shipments is being provided entirely by Syrian military units loyal to President Bashar al-Assad, who has surprised American officials with how speedily he has complied with an agreement brokered by Russia to identify and turn over his chemical weapon stockpiles. Intelligence analysts and Pentagon officials say the shipments will be vulnerable to attack as they travel past the ruins of a war that has raged for two and a half years. Asked over the weekend what the backup plan would be if the chemical weapons components were attacked […]