A leaked survey conducted for the Republican National Committee (RNC) found that a majority of President Trump's supporters don't believe that Democrats have a chance to win back the House during November's midterm elections.

Bloomberg Business on Tuesday published the survey, completed by Public Opinion Strategies polling firm on Sept. 2.

The results are likely to augment GOP fears about Trump's base not showing up for the midterms, when the president himself will not be on the ballot but House and Senate majorities are in play.

Fifty-seven percent of people who identified as strong Trump supporters said Democrats don't have a chance to win big, while 37 percent believe they do, according to the poll.

The majority of respondents - 71 percent overall - said it was "extremely" or "somewhat likely" that Democrats would be victorious in November, compared to the 25 percent who did not agree.

A number of election forecasters project that Democrats have an excellent chance of netting more than the 23 seats they need to take over the House majority, but half of self-identified Republicans told the poll they didn't believe in the "blue wave."

A report on the poll was sent to RNC officials urging them to convince Trump supporters that the threat from Democrats was real and that they needed to show up to vote in November.

"We need to make real the threat that Democrats have a good shot of winning control of Congress," the report obtained by Bloomberg said.

The internal RNC study found complacency among GOP voters was linked to how much they trust Trump.

"While a significant part of that lack of intensity is undoubtedly due to these voters' sentiments toward the President, it may also be partly because they don't believe there is anything at stake in this election," the authors write. "Put simply, they don't believe that Democrats will win the House. (Why should they believe the same prognosticators who told them that Hillary was going to be elected President?)"

The Hill has reached out to the RNC for comment.

Democrats have more than an 8-point lead in the RealClearPolitics average of generic House ballot polls, which tests preferences for which party should be in control of the House.

The RNC study also finds "a wide gender gap and generation gap," finding Democrats favored by women of all ages and also by men ages 18 to 44.

Only men older than 45 preferred the Republican candidate, by a 15-point margin.

"The Democrat(ic) party holds an image advantage over the GOP," the RNC study finds.

It states that the Republican Party should focus its messaging around Social Security and Medicare.

"The challenge for GOP candidates is that most voters believe that the GOP wants to cut back on these programs in order to provide tax breaks for corporations and the wealthy," the study states.

No matter what policy positions are put forth by the GOP, the study obtained by Bloomberg notes that the "determining factor in this election is how voters feel about President Trump."

"Those voters who 'somewhat approve' of Trump and those who support the President's policies but not his leadership style are the ones posing a challenge to the party," it states.