The gunmen walked into an apartment building before dawn earlier this month in the quiet Damascus suburb of Jaramana, went to the fifth floor and knocked on the door. When the police commander opened up, the men shot him dead and left. Syrian President Bashar Assad’s opponents appear to be resorting increasingly to assassinations of loyalist military officers in an escalation of their campaign to bring down the regime. At least 10 senior officers, including several generals, have been gunned down in the past three months, many of them as they left their homes in the morning to head to their posts.