The FBI did not "allow" Porter to "to work in the White House and peruse classified documents". The white house allowed him to "peruse classified documents" WITHOUT a security clearance (apparently along with more than 130 other staff who have not received security clearances).
The FBI does not issue security clearances, it does the background checks that are used to determine if someone should receive a security clearance. And in this case, the FBI informed the White House of the allegations against Porter months ago.
The FBI does not issue security clearances, it does the background checks that are used to determine if someone should receive a security clearance. And in this case, the FBI informed the White House of the allegations against Porter months ago.