Election officials and watchdog groups are bracing for the wave of sneaky or suspicious phone calls, leaflets and emails that typically hit battleground states in the final 30 days of the presidential campaign.

Young voters at Drexel University in Philadelphia, Penn. have already been targeted, with students reporting that flyers have been posted around campus warning that undercover police will be at the polls on Election Day looking to make arrests.

The flyer reads like a friendly letter to fellow students relaying a warning from an "Obama supporter": "He informed me that on the day of the election there will be undercover officers to execute warrants on those who come to vote based on the anticipated turnout," writes the anonymous student in the letter which was later posted on the Drexel College Democrats website. "He advised me if I had any outstanding warrants or traffic offenses I should clear them up prior to voting."

Political experts say the Drexel flyer is a classic example of voter suppression  a practice that involves scaring, angering, or confusing voters so that they stay at home on Election Day.

"The basic idea is that you intimidate people by saying that law enforcement is using the polling place to catch scofflaws&criminals&whoever. It's basically a deterrent to keep people away from voting," said Allen Raymond, a former Republican operative who went to prison for three-months in 2006 for his involvement in a scheme to jam the phones at headquarters of the Democratic get-out-the vote effort in New Hampshire in 2002.