Two things: (1) it's hard to get a warrant. This is a search warrant for the President's personal lawyer's office and covers privileged communications (obviously under the crime-fraud exception). The federal judge that signed this must have been shown some very serious evidence of a crime.

(2) Since SDNY executed this warrant, it (a) had to be approved by the Assistant Attorney General of the criminal division (department policy for searching lawyers' offices), and indicates that a second criminal investigation of the Trump admin is active.

So, big big deal.

We might soon see how serious he was when he said that he'll always protect DJT. Feds can dig quite deep and some sentences run in decades (assuming he did anything illegal.)

News sources are reporting the warrant was VERY broad.

So, now Mueller (through proxies) is applying more leverage, as expected, attempting to get yet another confidant of Trump in his snare. Cohn has reams of docs and provided plenty of testimony under oath - - now agents will examine all the docs they raked from the raid to determine if they can press the most common of all gambits: Lying to the FBI (or a court of record). If they can prove this, then they apply elbow grease to Cohn to try get him to desert and testify against Trump in exchange for a lesser sentence. But now Trump smells blood and could actually push the nuclear switch option and give the apprentice battle cry to Mueller "YOUR FIRED !". Trump could also pardon everyone the FBI snares, that is, if he doesn't get impeached, which seems unlikely with precedent being Clinton's brush with impeachment where the vote came down along party lines (failed).