But is that actually the case? Two leading pollsters in Iowa and New Hampshire aren't totally sure – though they say that even if the candidates can do little to sway voters this time of year, that doesn't mean the winter holidays cause public opinion to freeze like an ice pond.
"My guess is that caucus attendees are highly engaged politically and conversations will continue," said Ann Selzer, whose firm conducts The Iowa Poll for the Des Moines Register. "Are they going to candidate's events? Probably not. Do they have less time for reading or Web surfing? Probably. But they are still talking to people."
Selzer said the wide-open nature of this year's race, in both parties, makes the presidential race an irresistible topic, even as Iowans rush to buy Christmas presents.
Dick Bennett, head of the New Hampshire-based American Research Group says that while politics still might be off-limits for Christmas dinner conversation, Granite State voters aren't taking any sort of electoral vacation with their primary only a couple weeks away.
"The 24th and the 25th, they want that time [to themselves]," he said. "But I think beginning on the 26th and through New Year's, suddenly this is an important decision and it gets put back on the front burner, like anything else."
Bennett said the holiday rush hasn't made people any less willing to talk to pollsters, indicating an excitement about the election – and an electorate that still hasn't made up its mind. Once voters have settled firmly on a candidate, he said, their desire to stay on the phone for a poll drops off.
But it's still difficult to gauge the effects of the holidays on public opinion because there's no previous example for comparison. In 2004, the Iowa caucuses were in mid-January, meaning the mad dash of the final two weeks came after New Year's Day.
"We just have nothing to go on," Selzer said. "Anything is speculation based on nothing. I try to base my speculation on data or experience."