Edit 3:30: Judge Napolitano on if Susan Rice did anything illegal. His take on what she did is it might be espionage.
This scandal can and should be compared to Watergate, though it is vastly worse.
Watergate was a break-in of one office to get info on the campaign. This scandal is about undermining the incoming president of the USA through the use of America’s intelligence agencies.
If the unmasking of American names was done by Rice, that action is not in itself technically illegal as far as I understand. If Rice unmasked for any reason other than “national security,” it is illegal. Similarly, Obama’s lowering the secrecy status of that unmasked information so that more eyes within the intelligence community would be on it is not in itself illegal as far as I understand.
Leaking those names to the press is illegal. Since both Rice and Obama were responsible for setting up the conditions to make those leaks possible, it does seem that there is very significant moral culpability on both of their parts.
Here is a reasonable back-and-forth on this issue: Rice unmasked as Team Trump unmasker: What it really means.
An important point missed by Carlson in this discussion is: Not only is there no evidence of Russian hacking but the DNC refused multiple times to allow the FBI to examine the hacked server.