Despite surges in polling, fundraising and volunteers, Vice President Kamala Harris campaign chair insisted in a memo out Sunday morning that the Democratic candidate remains a clear underdog as the 2024 presidential campaign enters its final stages.

Since swapping out President Joe Biden for Harris in July, Democrats have reignited their hopes of defeating former President Donald Trump . However, in a clear effort to ward off complacency among still-jubilant members of the party, campaign chair Jennifer OMalley Dillon said the campaign will need to hammer home a message focused on linking Trump to an unpopular conservative policy manifesto and exploit their advantages in the ground game to win.

Make no mistake: we head into the final stretch of this race as the clear underdogs, OMalley Dillon wrote in the memo. Donald Trump has a motivated base of support, with more support and higher favorability than he has had at any point since 2020.

In 2020, the election came down to about 40,000 votes across the battleground states, OMalley Dillon continued. This November, we anticipate margins to be similarly razor-thin.

The memo came just ahead of the Labor Day holiday, which often signals the start of the most intense period in American electoral politics. It also comes as the first mail ballots will be sent to voters in North Carolina, a key swing state.

The plan OMalley Dillon laid out to win the battleground states focused on the Democrats ground game advantages, saying the campaign, Democratic National Committee and state parties have opened more than 312 offices and hired more than 2,000 staff members.

In an election that will be decided on the margins, Trumps campaign still lags far behind in the infrastructure needed to win in key battleground states, OMalley Dillon wrote, citing Democratic advantages in Pennsylvania, Nevada and Georgia.

On the messaging front, OMalley Dillon indicated that the campaign plans to continue to link Trump to Project 2025 but suggested the bigger fight will be over defining who Harris is.

While Donald Trump is a heavily defined candidate, voters do not know Vice President Harris or Governor Walz as well, she wrote. While we continue to ramp up our organizing and paid efforts over this final stretch, an aggressive campaigning schedule to introduce and define our ticket to the voters that will decide this election will be critical.

OMalley Dillons contention that the campaign remains a clear underdog is not necessarily backed up by public polling. Harris has a 47.1% to 43.8% lead over Trump in the national polling average as of Aug. 31, according to FiveThirtyEight , whose model of the election gives Harris a 57% chance of winning .

Election data guru Nate Silver, however, gives Trump a 55% chance of winning .