It’s rare to see President Barack Obama offer anything but unstinting praise for his former secretary of state, Hillary Clinton, but he took an unmistakable jab at her at a news conference Friday when it came to their views on the Syrian civil war.

Mrs. Clinton, whose instincts are more hawkish than those of Mr. Obama, plainly differs with him on how best to solve the Syrian conflict. In a recent TV interview she described U.S. efforts to arm rebels opposing the Syrian regime as a failure. This week she called for no-fly zone over Syria in an effort to curb the fighting. The White House does not favor such a step.