BZZZZZZ! Sorry. Wrong Answer.
Buckley was no conservative. A true conservative is a SoCon.
That leaves Bill Buckley out.
So your “challenge” is really a version of the no true Scotsman fallacy? The moment one names a conservative who supports legalization of marijuana, you declare “he’s no true conservative: true conservatives oppose marijuana legalization”.
The challenge was to name a conservative, not a conservative in Responsibility2nd’s crabbed, narrow redefinition of the movement, who supported marijuana legalization, and I and many other posters did so.