THE FIRST presidential debate, on foreign policy, was gratifyingly substantive, but inevitably it left some important questions unanswered. Because tonight's forum in St. Louis may be the last chance for the two candidates to debate these questions (the third and final debate, next week, is meant to concentrate on domestic policy), we offer a few issues we think still deserve attention.

Our chief question about Sen. John F. Kerry remains, much as it was before the first debate, about his conception of the scope of the war on terrorism and the proper response to it. Last week Mr. Kerry reiterated a narrow view, describing Iraq as a diversion from "the real war on terror in Afghanistan against Osama bin Laden." If Mr. Kerry means by this that the Bush administration shifted too many resources too quickly out of Afghanistan, that's a reasonable argument. But surely capturing Osama bin Laden and routing the remaining al Qaeda leadership would not be the end of Islamic terrorism. What, then, does Mr. Kerry think the "war on terror" means, and how best can it be fought?

Mr. Kerry said in the first debate that "Iraq was not even close to the center of the war on terror before the president invaded it." So why did he vote to give President Bush the authority to go to war at all -- even if he never expected Mr. Bush to employ that power so quickly and high-handedly? Now Mr. Kerry says of Iraq, "I'm not talking about leaving. I'm talking about winning." What does "winning" mean to Mr. Kerry? What would his goals there be?

As to Mr. Bush, the questions have more to do with his record than with his plans. Asked in the first debate about his miscalculations in Iraq, he chafed even at acknowledging missteps he had previously conceded. The problem, he said, was simply that U.S. forces achieved such a "rapid victory" that "more of the Saddam loyalists were around" to deal with afterward. Why didn't the administration heed warnings, even before the war, that the reconstruction would be long, difficult and dangerous? Why did it so doggedly resist sending enough troops? Perhaps tonight Mr. Bush could answer the question, dodged by Vice President Cheney on Tuesday, about former Iraq administrator L. Paul Bremer. Mr. Bremer now says he believed that U.S. forces in Iraq were too few from the beginning -- and that he was ignored when he raised such concerns.

One place name, also, was missing from the first debate that both candidates ought to address: Abu Ghraib. What do they believe should be the policy for handling and interrogating foreign detainees? Should the United States follow the Geneva Conventions, or employ coercive measures on prisoners it considers "illegal combatants" -- as the Bush administration has done at the cost of a damaging global scandal? Does Mr. Bush continue to believe that departing from the Geneva Conventions was the right course? And why has he been so reluctant to hold anyone in a position of power in his administration accountable for the outrages at Abu Ghraib, for intelligence failures or for other misjudgments in Iraq?