Alexandra Kerry, John Kerry’s daughter, at the Democratic Convention, July 29: “We were standing on a dock waiting for a boat to take us on a summer trip. (Our dog) knocked the (hamster) cage off the dock. We watched as Licorice, the unlucky hamster, bubbled down to a watery doom. But my dad jumped in, grabbed an oar, fished the cage from the water, hunched over the soggy hamster and began to administer CPR. Licorice lived!”

Barbara Bush, President Bush’s daughter, at the Republican Convention, Aug. 31: “We had a hamster, too. Let’s just say ours didn’t make it.”

OK, the evidence seemed clear: One candidate had bravely saved his children’s hamster. When duty called, he served. He even got wet. The other candidate had shirked his hamster duties. If you wanted a fur-blooded hero, you knew which guy to vote for.

But then …

Just days after the Bush twins exposed their father’s dismal rodent-rescue record, Karl Rove was spotted leaving Jimmy’s Pet Shop with a smug look on his face and a squirming bulge in his briefcase. “Nothing in here but my lunch!” he snarled to reporters, speeding off.

That evening Hamster Wheel Pets for Truth aired its first commercial:

“I was in the cage with Licorice. I know what happened because I was there,” intoned a solemn, graying hamster. “John Kerry did not save that animal. I did. I grabbed our water bottle and used its little metal nozzle to pry open the bars.”

The camera then showed another graying hamster — or perhaps it was the same one — saying, “John Kerry is lying about his heroism. I was watching from behind the picnic basket. All right, maybe I was in the basket, nibbling. But I did peek out, and what he says happened and what actually happened are as different as woodchips and shredded newspaper.”

Another (I think) hamster sneered: “That cage floated like a toy boat. All Kerry had to do was grab it, like he grabs Purple Hearts.”

The next day, Kerry asked Bush to denounce this scurry-ous ad. Instead, a new one aired that night:

“John Kerry says he saved Licorice on the way to a vacation. Not true,” said a tired-looking hamster. “He was never on a pier — never even owned a pair of Dockers. I know, because my cage was in his neighbor’s window, and I never saw him leave the house.”

When Kerry protested again, Bush called him a great hamster, er, hero. But then came another ad:

“John Kerry threw out his Licorice tchotchkes!” gasped an exhausted hamster propped up by someone’s hand. “A little bell and a stuffed mouse-thingy. How unpetriotic! Kerry’s toes should be gnawed raw, and I would personally like to do the gnawing.”

After this, Karl Rove reappeared at the pet shop, producing a dead rodent and demanding his money back.

And President Bush was up 39 points in the polls.