As the US presidential campaign overlaps with the season of the witch in three days - Halloween - Donald Trump masks are outselling Hillary Clinton masks, and critics say political correctness is stalking some university campuses, reports Hong Xiao and Ai HePing in New York.

Most polls now put the former US secretary of state ahead of the businessman to win the presidential election in 11 days, but when it comes to putting on the face of one of them in three days for Halloween, Trump is ahead, according to surveys of costume retailers.

While 200 million Americans are registered to vote this year, 171 million are forecast to don costumes on Oct 31.

For children, it will be knocking on doors for candy. For adults, it will be the third-biggest party day after New Year's and Super Bowl Sunday.

A record $8.4 billion is forecast to be spent on candy, costumes and decorations this year, according to a survey by the National Retail Federation (NRF) - more than any other year since the survey began in 2005.

Halloween sales last year were $6.9 billion. In the last election year, 2012, they were $8 billion, up 16 percent from the previous year. And in 2008, the year then-Senator Barack Obama defeated Senator John McCain (and popular costume inspiration Sarah Palin) sales were $5.8 billion - up 14 percent from the previous year.

Close to 70 percent of Halloween shoppers surveyed said they'll buy a costume. Most adults said they'll choose a witch or pirate costume, and more than 4 percent of adults over the age of 35 said they'll turn to the presidential election for their costume inspiration.

Donald Trump masks are currently outselling Hillary Clinton masks this Halloween 55 percent to 45 percent, according to retailers.

In the spirit

Spirit Halloween, a New Jersey-based company with 1,200 stores nationwide that make it the largest retailer for Halloween costumes, has a full line of Trump and Clinton masks made of latex or foam. They are made in China and Mexico, two countries that Trump has criticized for taking jobs away from Americans.

In late August, the retailer teamed up with Harris Poll, which surveyed 2,000 American adults on their costume choice. The top reason people said they would choose Trump for Halloween is to be funny, whereas the No 1 reason they gave for dressing up as Clinton is that they like her. The poll also found that twice as many Americans who want to dress up as Trump say they would do it to mock him.

Halloween costume manufacturers and retailers say that in normal presidential election/Halloween cycles, the candidate with the best-selling mask has eventually won the White House. Spirit Halloween's best-selling Halloween mask has correctly forecast the outcome of every presidential election since 1996.

"The ongoing joke is that we predict the election by whatever mask sells more, though I'm not sure if that will be the case this year," Mike Windsor, area manager for Spirit Halloween, told The Boston Globe.

At Rubie's Costume Co in Queens, New York, the world's largest designer and manufacturer of costumes, Trump masks are outselling Clinton masks 3-to-1, according to Howie Beige, Rubie's executive vice-president.

The best-selling candidate mask has been a pretty good predictor of who will take the White House, Beige said. "It's definitely worked for every single election since the Nixon era."

But he told Bloomberg Businessweek that two things are happening that make this election different: People are dressing up as Trump to both make fun of him and support him. And dressing up as Clinton is too much work.

"Ninety-eight percent of the buyers of full-face masks are men," he said. "When they buy a Hillary mask, they have to ask themselves, 'Am I putting on a dress or a pantsuit?' "

While this year's presidential campaign of both the Democratic and Republican candidates has been deemed by many as perhaps the most offensive ever, several colleges and universities across the nation are warning students not to wear Halloween costumes that in any manner may be offensive. And that has spurred critics to decry what they see as an emphasis on political correctness.

What to wear?