The special counsel’s office has informed President Donald Trump that he is a subject of its investigation but not a target, according to media reports earlier this week. This news set off a round of speculation as to the significance of the designation for the president. The simple answer is this: it is not a surprise, but it is also not good for him.

The distinction between a subject and a target is, at times, nuanced. “Subject” encompasses a very wide category. According to the United States Attorney’s Manual, a subject is “a person whose conduct is within the scope of the grand jury’s investigation.” In contrast, “a ‘target’ is a person as to whom the prosecutor or the grand jury has substantial evidence linking him or her to the commission of a crime and who, in the judgment of the route, is a putative defendant.” Put these two together and you have a clear result: A target who is not yet a putative defendant in the eyes of a prosecutor is, by nature, a subject. Trump may very well be a subject for that reason.

This topic of classification often arises when a prosecutor reaches out to an individual to obtain evidence from him or her. Every person has a Fifth Amendment right against self-incrimination. What this means is that a defendant — or possible defendant — cannot be coerced or forced to give statements to investigators. This is among the various reasons that prosecutors often ask anyone who may fall in the “subject” category to sit for a voluntary interview – if a person chooses to give a statement, that statement may be used in an investigation against him or her. The US Attorney’s Manual warns that subpoenaing a target “may carry the appearance of unfairness,” and judges can consider that such unfairness amounts to coercion in a particular case. If a judge decided so, it could poison the whole investigation. The fact that prosecutors steer toward voluntary interviews with subjects as well as targets indicates just how close these two categories often are in practice.

In certain quarters, Trump’s designation as only a “subject” after a year of investigation is cause to celebrate. The president’s team, however, should not get out the champagne. Being a subject is a very fluid state and is often liable to change. The fact that Trump is not a putative defendant at this moment only means that prosecutors do not have enough evidence to call him a defendant at this point. It does not mean that they cannot develop that evidence. For some, like Alan Dershowitz, the fact that the Department of Justice hasn’t developed such evidence over the course of the year means that a case against Trump doesn’t exist. The idea that the investigation would be concluded in a year was always a far-fetched notion, perhaps concocted by defense attorneys to undermine the investigation as it persisted beyond that point. The national security implications of Russia’s involvement in the US election, the possibility of a conspiracy between Russian actors and a presidential campaign plus the related probes of obstruction and Paul Manafort-like money laundering makes this perhaps the biggest and most complicated investigation that anti-corruption prosecutors in the U.S. will ever handle. Such complex investigations will not happen quickly. Nor should they.

Take the example of Congressman William J. Jefferson who was indicted in 2007 for a bribe scheme that occurred from 2000-2005. Or consider Alabama Governor Don Siegelan who was charged in 2005 for a racketeering conspiracy that ended in 2003. A grand jury indicted former Senator John Edwards in 2011 for conduct that occurred in 2007 and 2008. Likewise, it took two years to put together an illegal campaign donation case against Connecticut’s former Governor John Rowland, who was charged in 2014 for conduct that ended in 2012.

What’s more, there are two huge impediments that would slow down the current Russia probe. First, the investigation, by its nature, has to gather domestic and international evidence. Gathering evidence from overseas is extremely cumbersome for the Department of Justice. Criminal investigators have to work with colleagues in the DOJ’s Office of International Affairs to prepare extensive requests from foreign countries pursuant to Mutual Legal Assistance Treaties (MLATs). Each MLAT request is a detailed document outlining the DOJ’s need for evidence that investigators believe to be located in the foreign jurisdiction. Different countries provide varying levels of assistance, and the DOJ has no jurisdiction to conduct investigations in another country without the host-country’s cooperation.

Secondly, as the charges in the Special Counsel’s investigation makes clear, there has been an unprecedented level of obstruction directed at the inquiry. Investigators have had to parse, verify and disprove many of the statements made to them by witnesses. Indeed, the Special Counsel has had to develop enough evidence to build a case against each of the obstructionists whom he and his team has charged. This will slow down any investigation.

The notion that Mueller is misleading Trump is, however, equally dubious. While special agents are allowed to deceive witnesses in sting operations, prosecutors are prohibited from engaging in the same types of deception. Mueller is a renowned straight shooter. If Trump were a target, he would have told him.

Ultimately, being the subject of an investigation is still bad news for the president. No one wants to be told that his or her actions fall within the scope of a grand jury investigation. But this leak is good news for one person: Robert Mueller. The fact that the public is aware that he is not preemptively designating the president a “target” delegitimizes the idea that the investigation is an anti-Trump witch hunt. Make no mistake, Mueller’s target is Russian interference. Whether he takes down Trump in reaching that target still remains to be seen.