That's right, Joe, this is. Keeping in mind that we still don't know who will get arrested, or for what, this is a big fucking deal. When one of the President's inner circle is arrested and charged with a federal crime in an investigation at this level, it is a big fucking deal.
Let's remember, though, that the only way this leads to any prison time for anyone is as follows: if this is someone not too close to Trump personally (like Manafort) who did something not actually related to the campaign (like Manafort taking money from Russians and Ukrainians for personal reasons).
Flynn? He's safe. He has an absolute guarantee of a pardon. Kushner, and everyone else closely tied to Trump? Same deal. Manafort is in real danger, though, because he isn't a close Trump associate, and he can be indicted for matters unrelated to the Trump campaign. He was being watched before Trump hired him. Trump hired him anyway. Because Trump is a fucking moron (source: Tillerson, Rex). Does Trump pardon him to keep him quiet? Eh... I am skeptical of these kinds of things, but we'll see.
Regardless, even if it is just Manafort today, and for actions taken unrelated to the Trump campaign, that would still be, in Biden's words, "a big fucking deal." This, then, becomes a test of the political system.
The President's former campaign manager gets arrested and charged with federal crimes (again, it might not be Manafort-- I'm just going with the safest hypothesis here). How big a scandal is that? When the President's whole schtick is that he'll hire the best people because he's a businessman? A "yuge" one. Will the political system respond in that manner? No. Why not? Signals. John Zaller strikes again.
Trump will scream about "fake news" and Hillary and voter fraud and probably something about chem-trails or whatever other shit he gets from Alex Jones. The Republican Party will close ranks around Trump, especially if the only indictment is for Manafort's actions outside the Trump campaign. The result, then, will be that voters receive signals running in opposing directions: Democrats saying this is a major scandal, and Republicans calling it a nothingburger. Unless... Unless...
The neutral press will have a burden upon them. How do they cover something that will be, objectively, a major scandal, but with one entire party telling them that black is white, up is down, and 2+2=5 (hello, Mr. Orwell)? So far, they have pretty much failed. In the 2016 campaign, due to media failures, the electorate incorrectly perceived Trump as more honest than Clinton even though Trump is, by far, the most dishonest politician we have ever seen (here is his current PolitiFact scorecard, problematic though their method may be).
How will the neutral press handle this? I don't know. If they treat this the way they treated the 2016 campaign, though, and permit the GOP to assert that the arrest of someone in the President's inner circle is an insignificant "fake news" event, then that will not only inhibit our ability to respond to this scandal, but demonstrate the political system's inability to respond to any real political crisis.