Simple, go from Yellow to Red alert nationwide from now till the election.. No going through orange/elevated, go straight to red/severe, and do that till after every last vote is counted and in... it may be something of an inconveninence, but given what happened in Spain (the Conservative government was up 12 percent before the Madrid bombing, then after the bombing the Socialists won by 12%, a 24% move in the vote counts. They were scared into voting for the socialists, and Americans may I fear, if g_d forbid such a thing happened, vote for Kerry out of fear. It'd be better that they vote for Bush out of fear... a red alert could have the same impact the daisy girl/h-bomb had for Johnson against Goldwater.
absent additional intelligence, there is no reason to raise the terror alert just because some jihadi can use a camcorder and make a tape.