(Bloomberg View) —It’s hard to believe after four days of increasingly dire revelations about the president’s son, son-in-law, and former campaign manager, but true nonetheless: The basics of the Trump-Russia scandal have only changed mildly in the past year.

In 2016, Donald Trump publicly encouraged Russian interference while bestowing the U.S. adversary with far friendlier policy positions and rhetoric than that of his party. Today, a special counsel appointed after the president fired FBI Director James Comey is working to fill in details. So are the halting but real investigations in Congress, especially the one by the Senate Intelligence Committee.  The various investigations may have legal implications, but the big picture has been public for a long time.

There are three separate tracks to this scandal, and all potentially contribute to any possible premature ending of the Trump administration. The first is the drip, drip, drip of reporting from newspapers and TV news organizations, combined with the president’s actions and reactions. Sometimes critical events, such as the Comey firing, show up on this track.

The second track is probably more important since it’s the one that is powered by institutions designed to check the power of the president. Its timeline may look very different than the media’s telling of the scandal, though questions abound because of its secrecy: What is special counsel Bob Mueller’s investigation finding that we don’t yet have access to? As they comb through physical evidence and interview all the players and the witnesses, what story are they putting together? Meanwhile, what are the various Trump figures doing? Are any clearly in legal jeopardy — and if so any of them have information the prosecutors would love to see, and if so are they considering cutting a deal before it’s too late? If that’s the case, what if anything is the White House doing in response?

One thing is for sure: Reasonable expectations of where the investigations will lead are starting to get clearer. Here’s a quick scorecard:

It’s no longer possible that answers to all of those questions could add up to the “nothingburger” so often referenced by president and his allies. It is still possible that the worst offenses among Trump and his associated amount to extremely poor judgement and massively unethical behavior. It’s also possible that less is being covered up than it seems, and that the scandal amounts to a political embarrassment without legal implications. It’s possible that crimes were committed but that the president, despite his claims of being his own campaign manager, was uninvolved. And it’s possible that everything anyone has imagined (or feared) and more will turn out to be true — and that plenty of physical evidence exists to confirm it.While no one knows if or when Mueller will decide to prosecute anyone, the evidence is only one factor into what Congress eventually decides to do.

What we already know about the Russia scandal — along with the lawlessness of Trump’s disregard for normal presidential ethics and conflicts-of-interest — is more than enough to justify impeachment. But it’s also far from where impeachment and conviction is widely accepted as the only appropriate way to remove a duly-elected president.

That leaves the third track, which is the overall health of Trump’s presidency. The more power he loses overall, the more Congress will be willing to move against him. For Trump’s influence, popularity matters — or, more technically, what Richard Neustadt called “public prestige,” which is roughly defined as what those in Washington believe their constituents think about the president. For members of Congress, this is fairly straightforward, although still subjective: The more popular they think he is back home, the more likely they’ll give him the benefit of the doubt. Polling enters into it, but so do other measures of district sentiment. Remember, these are political professionals, and they are expert (and certainly think they are expert, which is what matters) at gauging the sense of their districts far more carefully than any poll can get at.

And the president’s professional reputation matters. Are they afraid he’ll find a way to make them suffer if they oppose him? Or do they think he’s a paper tiger? If he promises them no further revelations are forthcoming, will they trust him, or do they think he’s a liar?

That’s the context, by the way, into which any speculation about Trump firing Mueller or pardoning anyone must be placed. On the one hand, Trump might slow the investigations. But if he (further) damages his popularity and his reputation in doing so, it’s not at all clear he’ll end up with a win — especially not if overwhelming pressure means the investigations continue, just as they did after Richard Nixon fired Special Prosecutor Archibald Cox.

What we can say now is that this is one of the three most damaging presidential scandals of the modern era. Watergate ended with the resignation of the president in order to avoid certain impeachment and conviction, along with the imprisonment of many people, including high White House officials. Ronald Reagan survived Iran-Contra, but it was still a serious blow to his presidency. It cost Reagan about 15 points in the approval polls for over a year. His chief of staff resigned, and several high administration officials were charged with crimes, some of whom were convicted. It’s impossible to guess right now how Trump-Russia ends up, but it’s certainly not too early to put it into this general category of severe blows to a presidency.

This column does not necessarily reflect the opinion of the editorial board or Bloomberg LP and its owners.