Certain members of Obama’s Admin were running an illegal spying operation on multiple political campaigns (Trump, Carson, possibly Cruz).
They needed the FISA warrant on Carter Page to provide legal cover for the spying (I.e. how and where the information they obtained via spying originated from).
This involved high ranking members of the FBI. It also likely implicates Barack Obama, John Brennan, James Clapper, Harry Reid, Sally Yates, Samantha Power to name a few.
These people were involved in running and/or cooperating with the spying on the Trump campaign prior to the election, the President elect after the election, and the Trump administration after his inauguration.
They leaked false information to the media to fuel the Russian collusion hoax so that a special counsel (Mueller) could find justification for impeachment. The Mueller investigation failed to find high crimes and misdemeanors, so the Ukraine phone call (quid pro quo, bribery, extortion) narrative was the next attempt to impeach.
So now we’ve got articles of impeachment filed for “abuse of power” and “obstruction of congress”.
It’s a political sham designed to remove Trump from office In part so that the crimes for illegal spying will not be exposed.