By Election Day 2016, taxpayers will have paid out more than $16 million to fund Bill Clinton’s pension, travel, office expenses and even the salaries and benefits of staff at his family’s foundation, federal records show.

Since he left the White House in 2001, Clinton and his office have received more money through the Former Presidents Act than any other ex-president, according to a POLITICO analysis of budget documents.

Multiple sources familiar with Clinton’s funding say the special federal money has supplemented the salaries of some employees of the Bill, Hillary & Chelsea Clinton Foundation, a global nonprofit that has served as Hillary Clinton’s primary platform as she prepares for a presidential campaign expected to launch in coming weeks.

Critics for years have questioned why taxpayers need to support former presidents when they and their families can reap huge paydays, like the then-record $15 million book advance paid to Clinton for his 2004 memoir. But scrutiny of the act — and of the vast financial empire built by the Clintons — is poised to intensify as questions mount about the family’s commingling of personal, political, government and foundation business.

Bill Clinton’s payments from the fund, which is administered by the General Services Administration, appear to be compliant with government guidelines.

Clinton foundation officials brushed aside questions about use of public monies to supplement staff salaries there.

Clinton “is allocated funding for an office and for attendant costs (rent, utilities and salaries and benefits for staff),” foundation officials said in an emailed statement. “His office is allocated $96,000 per year for personnel salaries. GSA does not dictate the number of staff for whom the allocation is used.”

A Clinton spokesman also emphasized that no taxpayer money was used to purchase or maintain a private email server operated for the former president’s staff starting in 2007, which Hillary Clinton started using in 2009. Her use of the server to send emails as secretary of state has become the center of a swirling controversy about whether she skirted public records laws or State Department rules or compromised the security of top-secret national security information.

The server was funded entirely out of Bill Clinton’s pocket, according to his office.

Of the $16 million requested under the former presidents fund, nearly $3 million has been slated for staff salary and benefits, according to GSA budgeting documents.

The documents do not list the names or positions of the former presidents’ federally paid employees. But sources say that several Bill Clinton staffers who have been paid through the GSA have also been paid through the foundation or his personal office. They include Doug Band, the former White House aide who previously helped run the foundation’s Clinton Global Initiative, and senior foundation official Laura Graham, whose foundation salary increased from $74,000 in 2005 to more than $180,000 in 2013, according to tax filings. Another Clinton insider believed to have been on the GSA payroll is Bill Clinton’s chief of staff Tina Flournoy, a former union official who advised Hillary Clinton’s 2008 campaign and whose arrival on her husband’s staff in 2012 was seen by some insiders “as Hillary’s planting a sentinel,” according to a report in New York magazine.

Band and Flournoy declined to comment, while Graham could not be reached.

A representative for Clinton in 2001 told the Government Accountability Office that, in addition to the GSA money, “some staff compensation will be paid by the former president and his presidential foundation,” according to a 2001 GAO report. It made clear that most employees on the GSA payrolls of former presidents “also receive compensation from other sources.”

The GSA records used in POLITICO’s analysis — which include annual congressional appropriations requests, as well as enacted budget figures and information provided to Congress — shed light on the Clintons’ operation but also left unanswered questions.

Among the federal payments revealed are $947,000 for communications-related costs and “equipment” — an expense category which, according to a 2014 Congressional Research Service report, could include everything from furniture to “information technology hardware or software.”

GSA officials did not respond to questions about specific items, services or salaries funded by the act.

Although the Clintons footed the bill for the server used in their private email address, taxpayers indirectly have footed the bill to protect the server. That’s because it’s located at the Clintons’ suburban New York home, and, as such, is guarded — along with the rest of the property — by the Secret Service.

Addressing the matter in a Tuesday news conference, Hillary Clinton said, “The system we used was set up for President Clinton’s office. And it had numerous safeguards. It was on property guarded by the Secret Service. And there were no security breaches.”

The Secret Service provides lifetime protection for Clinton and other former presidents and their widows. That protection, for which the Secret Service does not disclose costs for security reasons, is separate from the perks provided under the Former Presidents Act.

The act was passed in 1958 to “maintain the dignity” of the presidency by subsidizing the correspondence of former commanders in chief and keeping them from falling on hard times, like those faced by Harry S. Truman. After leaving office in 1953, Truman acknowledged that he was living largely off proceeds from the sale of his father’s farm. In a 1957 letter to House Speaker Sam Rayburn, Truman predicted that, without some federal assistance, he would be forced to “go ahead with some contracts to keep ahead of the hounds,” according to Marie B. Hecht’s 1976 book “ Beyond the Presidency: The Residues of Power.”

Asked last year about the six-figure speaking fees raked in after his presidency by both Clintons, Hillary Clinton echoed Truman, complaining, “We came out of the White House not only dead broke, but in debt.”

By contrast, the Clintons, in their first year after leaving the White House, reported earning $16 million, mostly from speaking fees and book advances. By some accounts, Bill Clinton is worth more than any other living ex-president. The Clintons were worth an estimated $15.3 million in 2012, according to a Center for Responsive Politics analysis of a financial disclosure statement Hillary Clinton filed that year with the State Department.

“The notion of former presidents becoming paupers in their old age was laid to rest with Harry Truman,” said Pete Sepp, president of the National Taxpayers Union, which for years has urged Congress to scale back payments to the former presidents. “With the prospect of ex-presidents becoming even more deeply involved in post-career politics, there should be more motivation now than ever before to try and put reasonable limits on the load taxpayers are being asked to shoulder,” he said.

Citing “the controversy already surrounding the Clintons,” Sepp warned against the possibility of public funds “helping to subsidize activities that could aid presidential campaign operations.”

Sepp pointed to legislation introduced in the last two Congresses by Rep. Jason Chaffetz (R-Utah) to cap a former president’s federal benefits at $400,000 a year, with deductions equal to any private sector earnings beyond that threshold.

Chaffetz did not respond to a request for comment about the allocations for the Clintons. But in a statement upon introducing the bill in 2012, he said, “There’s little reason why American taxpayers should be subsidizing these former presidents when they’re doing fine on their own.”

Former presidents and their widows can decide which benefits to accept under the act, and how much to request for each category, though there are statutory maximums for certain categories.

A GSA spokeswoman said via email that the agency develops the budget for each former president “with a point of contact in each Former President’s office (generally an office manager).” Some of the categories “have known annual costs,” while others “are developed using historical execution levels,” said the spokeswoman.

And, since former President George W. Bush left office in 2009, he has outpaced Clinton in the value of benefits received from the GSA — $9.2 million versus $8.3 million — according to POLITICO’s analysis.

But Clinton still receives more than other presidents for his personal pension. He will receive $3.1 million in pension payments from the act through 2016, according to POLITICO’s analysis. That includes $218,000 this year and $221,000 next year, according to an appropriations request submitted to Congress last month.

That 2016 pension payment is more than the amount that any of the other former presidents are set to receive, according to the request. George W. Bush comes in second at $217,000, while his father, George H.W. Bush, and Jimmy Carter each are set to collect $207,000.

GSA also pays more for rent each year for Bill Clinton’s personal office than for those of any of the other former presidents, thanks to the personal office location Clinton chose on the top floor of an office building in New York City’s Harlem neighborhood.

The penthouse office, which is separate from the Clinton Foundation’s midtown Manhattan office, is slated to cost taxpayers $873,000 this year and next, according to GSA documents. That’s $9,000 more than George W. Bush’s Dallas office, which costs taxpayers the second most of the former presidents.

Clinton’s office is costlier per square foot and, at 8,300 square feet, more spacious than those of any of the other former presidents, according to the 2014 CRS report.

A Clinton spokesman previously stressed to POLITICO that not all of the space in Clinton’s office is usable.

Clinton’s rent would have been less expensive if he had chosen a lower floor, according to the 2001 GAO report. It said the rent per square foot for Clinton’s office was about 4 percent higher than that of a Social Security office located in the same building on a lower floor, without views of Central Park, the George Washington Bridge or Manhattan.

The office of George H.W. Bush in Houston is also on the top floor of a building and offered “good panoramic views,” the GAO report said. When it came to selecting Clinton’s office, “no other comparable properties exist in the area,” it said.