It is of course profoundly illegal. But I'm afraid the lack of serious investigation and prosecution we see here reveals that this was a "uni-party" operation. Neither the democrats or crony republicans wanted to see Donald Trump become president. Now that Trump has become president the media and uniparty are desperate to remove him by any means necesaary. Enter Robert Mueller.
The abject failure to hold Obama accpountable for the "Fast and Furious" gun running, IRS suppression of the Tea Party, the Benghazi cluster, surveillance of Fox news, etc. etc. likely mean that, unfortunately, the uni-party will probably succeed in covering up their illegal anti-Trump activities.