With the June, July, August and September surprises fizzled, the Romney campaign now must turn to an October surprise, and they think they’ve got one, which they’ve inexplicably previewed to a reporter (it’s not a surprise then).

According to a highly reliable source, as Mitt Romney and President Barack Obama prepare for the first presidential debate Wednesday night, top Republican operatives are primed to unleash a new two-pronged offensive that will attack Obama as weak on national security, and will be based, in part, on new intelligence information regarding the attacks in Libya that killed U.S. Ambassador Chris Stevens on Sept. 11 [...]

He added that they planned to release what they hoped would be “a bombshell” that would make Libya and Obama’s foreign policy a major issue in the campaign. “My understanding is that they have come up with evidence that the Obama administration had positive intelligence that there was going to be a terrorist attack on the intelligence.”

The source described the Republicans as chortling with glee that the Obama administration “definitely had intel” about the attack before it happened. “Intelligence can be graded in different ways,” he added, “and sometimes A and B don’t get connected. But [the Romney campaign] will try to paint it to look like Obama had advance knowledge of the attack and is weak on terrorism.”

Indeed, they’re making no attempt to hide this. Mitt Romney penned an op-ed this morning in the Wall Street Journal that references the Libya attack as part of a broader swipe against Obama’s foreign policy generally. Campaign surrogates like Republican Congresswoman Marsha Blackburn have made a point of this as well, calling the shift in the story on the Benghazi assault from a spontaneous event to a terrorist attack as “worse than Watergate.” They are clearly trying to litigate this into the debate on Wednesday, even though Jim Lehrer has already announced that the topics will mostly cover the economy.

Indeed, US intelligence has changed its story on Benghazi. Eli Lake claims that these intelligence sources knew within 24 hours that the attack was the work of militants, though they were slow to convey that impression to the public. He adds that the intelligence community distributed talking points to politicians suggesting that the attack resulted from a spontaneous protest. But the Romney campaign wants to take this a step further by suggesting foreknowledge of the attack. This is quite a leap, and if there’s evidence to suggest that, the campaign should present it.

But I just don’t think this will be a slam-dunk. It wasn’t but weeks ago that the Romney campaign insisted that they would not get distracted by anything but a focus on the lousy economy. Now their hole card concerns foreign policy. The country has pretty much indicated that the economy takes precedence. Furthermore, ANNOUNCING this as an October surprise would tend to lessen its impact. Finally, armed with the power of incumbency, the White House can just pull out some policy claim that blunts the attack, like today’s announcement that they thwarted a cyber attack.

But that’s the politics. We always hear about October surprises, and at this point they have become so ingrained in the public imagination that they may hurt more than help. But on the actual policy, it’s worth asking why did the White House withhold their information on the Benghazi attack for eight days.