I agree with most of the other comments here. As someone said, being elected, you can get away with things whereas if someone is HIRING you, they are the ones who will get blamed if you end up blowing a mission (no pun intended) cuz you were too coked up to keep tabs with your bosses in Langley.
I also think his admittance of such things is admirable. Clearly it has not negatively affected him (from what we can see), and would lead me to believe he has a more open mind. Most every educated person will tell you the war on drugs is a farce, but we can't get rid of it because lots of people are getting paychecks because of it. No one likes to see their budget go from a few million a year to zero, even if they know their job is bullshit