Current polls reveal that the economy is at the top of voters’ agenda and that they trust Senator Barack Obama to handle the ongoing crisis better than Senator John McCain. Today’s Rasmussen Daily Tracking Poll, for example, has Obama leading 51%-44% overall and by 63-32 “among voters who name the economy as the top voting issue.”

However, that same poll revealed that McCain has a whopping 74-24 lead “among those who say that national security is the highest priority.” Luckily for Obama, half the electorate says the economy is the most important priority, while only 19% “understand” it is national security.

Obviously, however, international events could change that calculus. In March 2004, an al Qaeda-affiliated terror group attacked Madrid’s train system just before the Spanish elections. The BBC reported 6 months later:

The evidence to date suggests that the Madrid attacks did not take long to plan or cost much to commit.

Given all that we know about the persistent vulnerability of open societies like the US, al Qaeda could do something to effect the election.

Remember the closing weekend of the close 2004 election? Osama bin Laden released a tape that Republican talking heads on TV interpreted as an endorsement of John Kerry, even as they gleefully boasted that “We want people to think ‘terrorism’ for the last four days…anything that raises the issue in people’s minds is good for us.”

That weekend, straight talking John McCain declared simply about the tape: “It’s very helpful to the president.”

Would al Qaeda strike the US in advance of the November 2008 elections in order to influence the results? Which candidate would al Qaeda want in office?

McCain promises to stay in Iraq to pursue victory, while Obama says the US will withdraw from Iraq over a period of 16 months and focus much more attention on Afghanistan and Pakistan.

Where would al Qaeda prefer to fight the US?

If the US is attacked by terrorists in the next month, or even if bin Laden releases another high profile tape, national security issues could become much more prominent in the election and McCain’s prospects could dramatically improve as a result.

Ironically, if Congress manages to “solve” the financial crisis soon, the economy might become less of an issue for voters.

Then again, political science research reveals that voters tend to form a perception of the economy and the parties fairly well in advance of the election, making the results fairly predictable by Labor Day of an election year. If this is true, then the debates, the reaction to the debates, and other apparent campaign “signals” are merely “noise.”