I also wrote bad then that this went all the way to the top, and could someday be a big problem even for the Great One
Yes, There Could Be Serious Legal Problems if Obama Admin Involved in Illegal Surveillance
"... If the stories are correct, Obama or his officials might even face prosecution. But, we are still early in all of this and there are a lot of rumors flying around so the key is if the reports are accurate. We just don’t know at this time. The stories currently are three-fold: first, that Obama’s team tried to get a warrant from a regular, Article III federal court on Trump, and was told no by someone along the way (maybe the FBI), as the evidence was that weak or non-existent; second, Obama’s team then tried to circumvent the federal judiciary’s independent role by trying to mislabel the issue one of “foreign agents,” and tried to obtain a warrant from the Foreign Intelligence Surveillance Act “courts”, and were again turned down, when the court saw Trump named (an extremely rare act of FISA court refusal of the government, suggesting the evidence was truly non-existent against Trump); and so, third, Obama circumvented both the regular command of the FBI and the regularly appointed federal courts, by placing the entire case as a FISA case (and apparently under Sally Yates at DOJ) as a “foreign” case, and then omitted Trump’s name from a surveillance warrant submitted to the FISA court, which the FISA court unwittingly granted, which Obama then misused to spy on Trump and many connected to Trump. Are these allegations true? We don’t know yet, but if any part of them are then Obama and/or his officials could face serious trouble.
Can a President be charged with a crime? Only once out of office. While in office, impeachment remains the exclusive remedy in order to avoid a single judicial branch trying to overturn an election, such as a grand jury in any part of the country could. Once out of office, a President remains immune from civil liability for his duties while President, under a 1982 decision of the United States Supreme Court. However, as the Nixon pardon attests, nothing forecloses a criminal prosecution of the President after his presidency is complete for crimes against the country. Obama, the Constitutional lawyer, should know that...."
More at the link, including specific statutes