For all the abundant controversies and screw-ups that have characterized President Trump’s time in office, it is the Russia scandal that will define this presidency more than anything else. And it may be time to reassess how it’s going to play out.

I say that because cynical analysts like myself have assumed up until now that the story will proceed in an almost orderly fashion. Special counsel Robert S. Mueller III will issue more indictments, reveal more wrongdoing by Trump and his associates and issue some kind of final report that will stand as a key historical document explaining one of the worst scandals in American history. The president will continue to call it a witch hunt, and his party will stand behind him. They will justify, excuse and explain away everything Trump and those around him did.

No matter what Trump is revealed to have done, it will be virtually impossible for him to be impeached and convicted, since that would require the agreement of a significant number of Republicans in the Senate, and they won’t see it in their interests to remove him from office. Their own fortunes are too deeply enmeshed with his, and their constituents wouldn’t stand for it. No matter how bad it gets, from where they stand, Trump being removed would be even worse. So Trump will stay in office, we’ll have two more years of scandal and increasingly erratic behavior, and in 2020 we’ll have another close election as Republican voters once again rally around their candidate, no matter how awful he might have proved himself to be.

That’s what has seemed like the most plausible progression of events given all the political, institutional and legal constraints that structure our system, and the interests of everyone involved. But there’s something important to keep in mind about presidential scandals. The amount of damage they do is a function of the facts of the case. Nothing could have saved President Richard M. Nixon given what he was revealed to have done in Watergate. And no matter how hard they tried and the resources they threw at the effort, Republicans couldn’t create a major scandal for Barack Obama for the simple reason that he never did anything scandalous, except in the fevered fantasies of conservatives.

But a president’s ability to weather a scandal is also a function of the strength he carries with him. And Trump could well get weaker and weaker over the next two years.

Just think about how he looks right now. The man widely regarded as the sanest of his national security team just quit, not long after Trump got rid of his attorney general and had trouble finding anyone who wanted to be his chief of staff. He’s about to force a government shutdown in order to advance a widely unpopular policy. A majority of the public believes he obstructed justice. He just suffered a historic defeat in the midterm elections. The stock market, previously his favorite metric of his success, has been swinging wildly. His former personal lawyer, campaign chairman, deputy campaign chairman and national security adviser have all pleaded guilty to crimes. His administration, his transition, his inauguration, his campaign, his foundation, and his business are all under investigation by various authorities.

All of that, and whatever else is on the way, affects Trump’s ability to withstand the Russia scandal. We saw just in the past couple of days how he was about to make a rational decision and put aside his dream of a border wall to avoid a government shutdown, then he was essentially forced by a mini-rebellion in right wing media to backtrack. The willingness of figures such as Rush Limbaugh and Laura Ingraham to attack him over that issue shows that their support is not absolute; he has to keep satisfying them to maintain it. The same is true of some Republicans in Congress, who were angered by Defense Secretary Jim Mattis’s resignation and Trump’s sudden announcement that he’d be pulling troops out of Syria.

Now consider that the Russia scandal is going to accelerate in the next couple of months. Mueller may be nearing the end of his work; NBC News reports that he plans to deliver a final report to the Justice Department by the end of February, a report that will almost certainly be made public one way or another. We still don't know exactly what the former Trump aides who have been talking to Mueller have told him, and what indictments could result. In addition, come January, Democrats in the House will begin holding their own hearings on the scandal, likely uncovering more information and bringing it before the public.

Trump could withstand all that if he was strong in other ways. If his party was unified behind him, and if the public as a whole thought he was doing a good job, voters might decide that whatever they thought of the big scandal, it didn't change their overall view of him. That's how Bill Clinton survived impeachment. But everything else that's going wrong reduces Trump's ability to dismiss the Russia scandal.

Now add in the fact that there will almost certainly be other scandals on the way. If and when Democrats get a hold of his tax returns, the chances that there will be nothing in them that is at a minimum appalling and at a maximum criminal are, given everything we know about Trump, approximately 0.0001 percent.

Nothing is guaranteed, of course. But all this suggests that as we march toward November 2020, Trump could get weaker and weaker, rendering him increasingly unable to avoid being defined by the Russia scandal. And what if, as many economists expect, the economy slows down some time soon? He’ll continue bleeding support, slowly and steadily.