In May 2017 when special counsel Robert Mueller began his investigation of Donald Trump’s presidential campaign, the country strapped in for a long, strange trip. Destination? We’d know when we got there.

Mueller was tasked with finding any coordination between the Russian government and individuals associated with the campaign, plus pursuing “any matters” arising from the investigation. So far, Americans have heard lots about those other matters, including serious legal trouble for Trump associates Michael Flynn, Michael Cohen and Paul Manafort. But no evidence has come to light yet proving collusion between the campaign and Russia to swing the election for Trump.

Much of the recently expended oxygen was over Cohen’s guilty plea for campaign finance violations. Court papers reveal Cohen’s also been sharing with Mueller’s team his knowledge of “core Russia-related issues.” The same goes for Flynn. He’s been so helpful that Mueller recommends Flynn not get prison time for lying to FBI agents about his conversations with the Russian ambassador.

There are at least two reasons for Trump to be worried about the direction of the special counsel’s investigation. The first is that Mueller’s mandate is so broad. Typically, law enforcement authorities identify crimes and then pursue the culprits. Mueller, in effect, is working the opposite strategy. He was pointed in the direction of a coterie of campaign-related suspects — and, by association, the president — then was given permission to bore down as deep as he chooses to find crimes. Those crimes include lying to the investigators.

Mueller is already responsible for a slew of indictments and convictions. He hasn’t finished, and with each step he takes, the shadow of scandal lengthens over Trump’s presidency. The special counsel faces no time limit on his activity. He works independently from the Justice Department. When does Mueller wrap up? When does he determine he’s no longer building a larger case but simply rooting out felonies as a means to its own ends? When Mueller says so, probably.

The risk of a special counsel probe becoming a perpetual prosecution machine is why the Tribune Editorial Board looks skeptically at calls for these independent investigations. They can get out of hand. Such mechanisms should be employed rarely, in situations where there’s compelling evidence of a serious crime when normal law enforcement channels aren’t available because of a conflict of interest. Mueller’s probe passes our test because Russian meddling is a threat to democracy and because Trump fired FBI Director James Comey, who had been leading the investigation.

If the first reason for Trump to be worried about his presidency is the breadth of the special counsel’s mandate, the second reason is his own reckless conduct. After all, Trump himself is the reason Mueller is all up in the president’s grill. If Trump had maintained discipline and allowed Comey to conclude the FBI investigation, there’d be no special counsel. But Trump couldn’t help himself, fired Comey, blabbed about it and now can be reasonably accused — at least in the public’s mind — of obstructing justice.

Once in swing, Mueller’s investigation was empowered to pursue “any matters.” In one major step, Mueller referred an investigation of Cohen to federal prosecutors in New York. That’s what led to Cohen’s guilty pleas on charges including campaign law violations for arranging payoffs to women who said they had affairs with Trump. Cohen implicated Trump in that crime, but the president denies it.

Proof of such reckless behavior by Trump could lead to his impeachment. Are there more allegations of crime in Trump’s orbit for Mueller to identify? Will Trump be accused directly of illegal activity? These are questions Trump wakes up pondering each day and then rails about on Twitter — instead of focusing intently on his other responsibilities as president.

To Trump and his supporters, the Mueller investigation is a witch hunt. To foes of the president, Mueller appears to be making their case that this president is unfit to hold office. To the detriment of the entire country, Trump’s administration appears distracted and prone to chaos. Getting caught in the sights of a long-running special counsel probe is a terrible look for a president.

Mueller is a trustworthy figure pursuing a legitimate assignment. He needs the independence to conclude his investigation on his own timeline, and then disclose the results. But the sooner he finishes, the better off the country will be.