Could Petraeus even get a security clearance anymore?
"Normal" people couldn't. But, Sandy Berger was able to get a clearance again after his shenanigans (removing classified info from the National Archives).
“Could Petraeus even get a security clearance anymore?”
that part is easy: President Trump grants Petraeus a pardon,which wipes his record clean, and then orders Petraeus’s security clearance. Easy, Peasy. If not necessarily wise.
“Could Petraeus even get a security clearance anymore?”
POTUS can grant any clearance to anyone he chooses and for any reason he chooses.
Could Petraeus even get a security clearance anymore?
Not in a real world, where we keep dangerous and/or unreliables from getting a security clearance.