In what can perhaps best be described as an act of appeasement, the Justice Department has announced that its inspector general will examine whether the FBI acted out of political motivation in conducting its 2016 investigation into links between Russia and the Trump campaign.

This comes in response to President Donald Trump’s tweet that he will “officially” demand that the Justice Department investigate whether the department or the FBI “infiltrated or surveilled the Trump Campaign for Political Purposes,” including whether this occurred at the direction of anyone in the Obama administration.

The move by the Justice Department - which was undertaken at the order of Deputy Attorney General Rod Rosenstein - is meant to temporarily mollify Trump in the face of what is a dramatic escalation of his ongoing effort to delegitimize special counsel Robert Mueller’s investigation. Here are three big takeaways:

Nothing will ever be enough. The idea that the Trump campaign was improperly “infiltrated or surveilled” is a reference to the “FBI informant” that Trump and his allies have railed about lately, claiming the FBI “spied” on his campaign. Trump’s allies in Congress have been demanding that the Justice Department release all documents related to this informant, a longtime intelligence source. The department has refused, on the grounds that so doing would compromise ongoing intelligence operations and put lives at risk.

We now know a lot more about this informant. The Post and the New York Times have both confirmed that he is a retired American professor and that he did in fact contact several Trump advisers during the campaign to gather information from them. But he was sent to do this after the FBI had obtained evidence that those advisers had questionable contacts involving Russia during the campaign. The FBI determined that Trump adviser George Papadopoulos had been told that Russia had dirt on Hillary Clinton in the form of “thousands of emails.” In other words, this “spying” was actually done in concert with what appears to be a legitimate counterintelligence investigation.

We don’t know what the IG’s probe will find. But here’s the point: Even if it confirms that the investigation was by the books, as is likely, it won’t matter. The position of Trump and his allies is that the investigation is inherently illegitimate to its core, so no fact-based examination of it can ever possibly change this. If the IG doesn’t conclude what Trump and his allies want him to conclude, they will simply scream “Coverup!” and move on to the next set of lies about the probe.

The system is probably holding - for now, anyway. Some are worrying that DOJ’s willingness to initiate the IG probe in response to pressure from Trump is a sign that the system is failing. I think this may be premature. A lot will turn on Trump’s next moves. Will he dismiss the IG examination as insufficient, and demand a full fledged DOJ investigation into the FBI’s conduct of the Russia probe? Or will he be temporarily mollified by the IG’s involvement?

If Trump opts for the latter, it’s possible to see an endgame here that isn’t too alarming. Yes, Rosenstein’s cave sets a terrible precedent in terms of eroding law enforcement’s independence from presidential pressure, by validating a demand from Trump that is nakedly political and rooted in a charge law enforcement corruption that is entirely baseless. But in the end, the IG could find that the investigation was not politicized, reaffirming its legitimacy. As noted above, Trump will scream that this is a cover-up. But his actions will matter more at that point, and if he does nothing, the Mueller probe may end up continuing until it finds the full truth, and the system will basically be holding. With a caveat:

The GOP’s enabling of Trump could get even worse. There are several possibilities here. The first is that Trump is not satisfied with the IG move and orders a full DOJ investigation of the FBI’s handling of the Russia probe. This could lead to resignations by Rosenstein and possibly FBI director Chris Wray. “If Trump says, ‘I’m ordering the Justice Department to open a criminal investigation, that’s the moment when people have to think about resigning,” Stephen Vladeck, a law professor at the University of Texas at Austin, told me today.

Or, alternatively, if Trump allows the IG probe to proceed and it doesn’t find what Trump wants it to, Trump may take action at that point, by firing Rosenstein or trying to remove Mueller. This is particularly awful to contemplate, as it would come in defiance of the IG’s fact-based validation of the Russia investigation. In both of these scenarios, pressure would mount on congressional Republicans to act, by, say, legislatively protecting the Mueller probe or its findings, or by beginning an impeachment inquiry.

As Vladeck put it to me, the moment at which Trump genuinely “subverts DOJ processes” will create “a really important inflection point for congressional Republicans.” There isn’t any particularly good reason to assume that Republicans would do the right thing, and at that point, we would be in a very dark place. But it really may not come to that.

Greg Sargent is a columnist with The Washington Post.