Today’s big news is that, during an appearance on NBC’s “The Today Show”, John McCain said that the question of when American troops can return from Iraq is “not too important.”

Assorted Democrats—including John Kerry on a conference call set up by the Obama campaign—have already slammed McCain for the comment. For its part, McCain’s camp has accused Democrats of taking the senator’s words out of context, and this afternoon rolled out Joe Lieberman to defend the GOP nominee.

But rather than covering this latest skirmish simply as a “gaffe” by McCain, or as a he-said, she-said exchange of campaign rhetoric, the press might consider stopping for a second to notice that there’s a genuine policy disagreement here.

Let’s look at what happened. Asked by Matt Lauer whether he now had “a better estimate of when U.S. forces can come from Iraq,” McCain replied:

No, but that’s not too important. What’s important is the casualties in Iraq. Americans are in South Korea. Americans are in Japan. American troops are in Germany. That’s all fine.

This is an entirely coherent position—and it’s the same position that McCain alluded to when he said in January that he could see U.S. troops in Iraq for the next 100 years, provided they’re not being attacked. In other words, McCain envisions using Iraq as a base for U.S. troops, in order to advance American interests in the Middle East, long into the future.

Obama disagrees. He wants to withdraw U.S. forces as soon as it’s practicable—in part to focus our finite military resources on the ongoing struggle in Afghanistan and the fight against Al Qaeda; and in part because he believes that an ongoing U.S. troop presence in Iraq would only inflame anti-American sentiment in the Muslim world.

Last time around, when McCain made his “100 years” comment, the press ended up focusing on whether Democrats were distorting his words (which they were, as we pointed out at the time). But lost in that brouhaha was the reality that McCain’s “100 years” remark revealed an important policy difference between himself and the Democrats. His remarks this morning make that difference even clearer.

The question of whether we want to leave U.S. troops indefinitely in the most volatile region in the world is a momentous enough issue that it deserves a full and open debate. The press should use McCain’s comment as a chance to have that debate, rather than just transcribing the competing bits of campaign rhetoric that his statement touched off.

Zachary Roth is a contributing editor to The Washington Monthly. He also has written for The Los Angeles Times, The New Republic, Slate, Salon, The Daily Beast, and Talking Points Memo, among other outlets.