With just six days until Election Day, Nancy Pelosi is confident Democrats will take back the House with more than enough seats.
The House minority leader has been privately expressing to donors and top advisors that she's cautiously optimistic about her party's chances of gaining at least 30 seats in the House.
Democrats need to flip 23 seats to win a majority. Experts give the party good odds to overtake the GOP. Data analyst Nate Silver's FiveThirtyEight gives Democrats an 86 percent chance of retaking the House.
Yet she also has insisted that Democratic election organizations such as the Democratic Congressional Campaign Committee, or the DCCC, cannot let up in their get-out-the-vote efforts with just under a week left until Election Day, according to sources familiar with the discussions.
These people spoke to CNBC on condition of anonymity as these discussions were deemed private.
Pelosi, who will likely become speaker again if Democrats pull off a win, made her confidence clear Tuesday night in an appearance on the CBS program "The Late Show with Stephen Colbert."
"What now I'm saying is, we will win. We will win," Pelosi said during the interview.
A Pelosi aide noted this is the first time she's made such a prediction. She has been more specific about her confidence in private.
A spokesman for Pelosi declined to comment further.
Pelosi's allies point to Democrats' fundraising and grassroots campaigning as key reasons for party leaders' confidence.
"We have the A-team on the field in terms of candidates, we've outraised the Republicans, we see historic mobilization and the message on health care is overwhelming Republican incumbents," said a source familiar with Pelosi's thinking, who declined to be named. "Pelosi is a numbers person. She comes to this conclusion very carefully."
The DCCC has outraised the rival National Republican Congressional Committee, the fundraising arm for GOP House candidates, by a significant margin. According to the nonpartisan Center for Responsive Politics, the DCCC has brought in more than $250 million throughout the 2018 election cycle while the NRCC has raised just more than $174 million.
The NRCC, though, has more cash on hand going into the final six days of the campaign, with $32 million in its war chest compared with $16 million for the DCCC.
DCCC Chairman Rep. Ben Ray Lujan, D-N.M., acknowledged in various interviews over the weekend that he too has confidence in Democrats going into election night.
"We built our strategy around our candidates," Lujan told Fox News Sunday. "Incredible men and women with records of service, many of who have served our country in the U.S. military. Former CIA officers, FBI agents who have committed their lives to keeping our country safe. And they're connecting with the American people talking about their personal stories."
The NRCC shrugged off Pelosi's comments on the Colbert show and said its ultimate focus is maintaining control of Congress.
"Nancy Pelosi can pontificate on late-night talk shows all she wants — Republicans are focused on closing strong in the battleground districts that will determine the majority," NRCC spokesman Jesse Hunt said in a statement to CNBC.
Still, some people close to the Democratic leadership remain concerned about recent immigration headlines, particularly President Donald Trump's attacks on the migrant caravan heading toward the U.S. but which is hundreds of miles away from the U.S.-Mexico border. These people say his attacks could invigorate Republican voters in Southwestern states such as New Mexico, Nevada and Arizona.
The president has seized on the news about the migrants, who are seeking asylum. He has made it into an election issue by claiming Democrats will only soften border security if they win in November.
Trump ordered more than 5,000 active-duty military troops to deploy to the southern border by the end of the week.
Republican strategists have also seen the migrant caravan as a boost of enthusiasm to their base.
"The caravan has been something Republican base voters are watching very closely and its kept them engaged over the last week," said one GOP strategist, who spoke on the condition of anonymity because of his involvement in the midterms. "It's something Democrats didn't want to see into the election because they don't know what to do about it."
This same strategist, however, concluded that Democrats will likely make inroads into the House and predicted a gain of at least 30 seats – just like Pelosi did.