MANCHESTER, New Hampshire — With the Iowa caucuses and New Hampshire primary only five months away, polls suggest Joe Biden, Elizabeth Warren, and Bernie Sanders are the top three favorites to win the Democratic presidential nomination. But mid- to low-tier presidential candidates are framing their struggle to gain traction in primary polls as a positive rather than a liability, pointing to historical trends and signs of progress in their own campaigns.

“We have never had a candidate who was ahead in the polls this far out who has ever gone on to be president,” New Jersey Sen. Cory Booker, 50, told reporters Saturday at the New Hampshire Democratic Party convention. “Thank God,” he added, that he is not further ahead in the polls right now. “The candidates that win from our party that energize the kind of movement elections we want to see are folks that were considered long shots at this point. Carter, Bill Clinton, Barack Obama were all behind.”