The recent suicide attacks show the bombers are able to move their explosives through a vast network of Iraqi police checkpoints.
Those checkpoints are extremely well-manned in advance of the election, but as CBS News correspondent Elizabeth Palmer reports, they have one fatal flaw.
It's called the ADE651 explosives detector. About 2,000 of them have been issued to Iraqi police.
The manufacturer's video claimed the device can find hidden guns and bombs in vehicles or other hiding spots, as long as the user moves his feet to generate static electricity.
The trouble is, they simply don't work.
"They're totally useless," former Iraqi National Security Advisor Moaffak al Rubaie tells CBS News. "I call them 'The Big Lie.'"
U.S. military officials warned Iraq's government not to buy the devices.
A few weeks ago, British businessman Jim McCormick, who sold them to Iraq, was arrested on charges of fraud through misrepresentation in the U.K. He has been freed on bond.
An Iraqi government spokesman said last week that Iraq was suing McCormick's company, ATSC, for the value of the devices.
So, why are Iraqi police still using them, especially at this critical time ahead of a national election that militants are clearly hell-bent on disrupting with bombs?
"There's no shadow of doubt in my mind that there is corruption behind it," Rubaie tells Palmer.
In other words, a scam which may have seen a handful of crooked officials agree a deal to purchase the useless detectors in exchange for a kickback.
That deal is now putting lives - as well as Sunday's crucial election - at even greater risk.