Washington (CNN) President Donald Trump's campaign donors -- big and small -- are increasingly helping to foot the legal expenses the President's campaign and his son , Donald Trump Jr., are facing related to the investigations into allegations of collusion with Russia during the 2016 campaign.

Trump's 2020 re-election campaign is driving a steadily rising share of its contributions to the lawyers representing the Trump campaign and the President's son. Legal consulting fees account for $1 of every $10 the campaign has spent this year, according to a review of campaign finance records

And last financial quarter, 24% of the campaign's legal bills bankrolled the legal fees of Trump's eldest son, who has drawn the attention of Justice Department special counsel Robert Mueller because of his meeting last summer with a Russian attorney he believed would provide him with incriminating information from the Russian government about his father's opponent Hillary Clinton.

Some of the campaign's more than $2 million in legal spending this year is due to the campaign's efforts to comply with records requests from the special counsel and the congressional committees that are also investigating Russian interference in the 2016 campaign.

It's not clear precisely what share of the campaign's legal costs are tied to the Russia-related investigations beyond the $318,000 disbursed to Trump Jr.'s attorneys. The Trump campaign's executive director Michael Glassner did not respond to CNN requests for comment.

But while the Republican National Committee, which this summer began footing some of the President's personal legal bills related to the Russia inquiries, has walled off donations to its general coffers from its legal fund, every dollar donated to the Trump campaign can be used to pay for legal expenses.

The RNC system means that legal expenses are largely funded by the party's wealthiest donors who contribute to the legal fund to comply with campaign finance limits while also cutting six-figure checks. The Trump campaign, it appears, can draw as much from those who make the maximum contribution as from those who send in $10 and $50 checks to fund legal expenses.

"What this means is that people who are giving to help re-elect Trump are actually paying for legal fees -- and that money will not be there during the election," said Larry Noble, the former general counsel of the Federal Election Commission who is now senior director at the Campaign Legal Center, a nonpartisan group of election law experts.

Just as it did during the 2016 campaign, Trump's campaign committee has continued to chase small-dollar donors with a steady stream of fundraising emails -- none of which have so far appealed to donors' desire to foot the campaign's and the President's multimillionaire son's legal bills.

The Trump campaign on Monday touted its reliance on small-dollar donors, noting that $1.2 million of its $10.1 million fundraising haul last quarter came from contributions of $200 or less.

"Our latest report on campaign fundraising demonstrates that support for President Trump's policies and passion is stronger than ever. Most importantly, we continue to see regular Americans make small donations in record numbers for a non-election year," Glassner, the campaign's executive director, said in a news release.

The Trump campaign has raised more than $25 million in the first nine months of this year, $10 million of which was raised between July and the end of September -- during which the campaign paid out more than half of its total legal expenses for the year.

The arrangement raises questions about the motives behind the Trump campaign's unprecedented level of activity for an incumbent president's re-election campaign more than three years before the re-election contest takes place.

"Many first-term presidents haven't even started their campaigns by this point," Noble said. "His beginning an unnaturally early campaign is paying off."

Trevor Potter, a Republican former chairman of the Federal Election Commission, called the Trump campaign's early fundraising "unprecedented" and raised questions about how upfront the campaign is being with its donors.

"We're in an unprecedented situation and it's all new territory. The key question here is what do donors know and what are their expectations?" Potter said.

The Trump campaign's other major expenses include paying for campaign rallies Trump has held and spending on Trump campaign-branded merchandise -- such as the famous "Make America Great Again" hats.

Bradley Smith, a former Republican FEC commissioner, said that while the campaign's legal spending appears "high," the increased spending is a reflection of the controversies and legal claims swirling around the Trump campaign.

Beyond the Russia inquiry, the Trump campaign has faced a series of other legal issues tied to the President, including most recently a subpoena for documents relating to women who have accused Trump of sexual assault

The flood of legal issues has left the Trump campaign in 2017 -- a non-election year -- nearly doubling Mitt Romney's 2012 campaign spending on legal fees

But the campaign's higher legal spending also reflects the campaign and Trump's decision to allow donors to foot the costs related to the Russia inquiry.

The Trump campaign has paid attorneys representing Trump Jr. in relation to the Russia investigations nearly $318,000. That's in addition to nearly $200,000 the RNC has paid to foot Trump Jr.'s legal bills so far.

The Trump campaign payments for Trump Jr.'s legal bills have risen from $50,000 in the summer to $267,924 last quarter.

Trump Jr. was a prominent surrogate for his father during the 2016 campaign, but was employed by neither the RNC nor the Trump campaign. There is no indication that the Trump campaign or RNC are footing the legal bills for any other Trump campaign representatives, though others have also had to retain lawyers in relation to the Russia probes.

The RNC this summer did, though, begin paying for the President's personal legal bills stemming from the investigations into Russian interference in the 2016 campaign, which are also examining questions of obstruction of justice on the President's part.