As Donald Trump crisscrossed the nation on his presidential campaign, he traveled with an official Secret Service detail — in keeping with a law passed by Congress the day after Robert F. Kennedy was assassinated, in 1968.

Trump, a longtime public figure and celebrity, supplemented his Secret Service phalanx with his own private security force. His chief bodyguard, a retired New York City cop named Keith Schiller, can be seen looming in the background of countless campaign appearances. But Schiller isn’t going anywhere anytime soon. Despite the fact that it’s standard practice for a president-elect to put security entirely in the hands of the Secret Service, Trump is also maintaining that private army, an unconventional arrangement that one former agent called “playing with fire,” according to a Politico report.

Law enforcement officials interviewed by Politico warned that this unusual arrangement has already complicated the job of the Secret Service agents who undergo rigorous crisis training throughout their careers. Agents reportedly criticized Schiller as slow to react last spring when a man rushed the stage as Trump spoke in Dayton, Ohio. While some Secret Service agents tackled the man and others shielded Trump, it took Schiller a moment too long to move. Schiller has also been seen wading into the crowd during the president-elect’s “thank you” rallies to help other private security agents eject protesters at Trump’s behest, raising questions about the use of force and prompting lawsuits. The Secret Service is known for its discretion; Schiller, a longtime loyalist, was retweeting tweets about “Criminal President Obama” as recently as Nov. 6.

While complaints from unnamed Secret Service agents assigned to the Trump detail might be dismissed as mere backbench carping, his unconventional security arrangements are quickly racking up costs. On the campaign trail, Trump spent more than $1 million on private security contracting, eclipsing the Clinton campaign, according to Federal Election Commission reports compiled by Politico. Earlier this month, New York City asked the federal government to reimburse it for providing police details around the clock at Trump Tower, on Fifth Avenue, through the transition. The estimated cost: $35 million by Inauguration Day.

Rallies paid for by Trump’s campaign, or through private funds, are one thing. But Trump is no longer just another Manhattan billionaire with a retinue. He’s the president-elect, certified by the Electoral College on Monday, and should begin to show how he’ll govern. And how he’ll “unify our great country,” as he vowed the morning after his election. That effort will only be impeded if he remains aloof, behind his own private police force.