You may not like the reference, but: Nixon (a Republican) started the "drug war". Nancy Reagan with her "just say no" campaign was totally anti-drug. But in general: most of the Republicans are opposed to MJ legalization; but you will find a non-trivial number of Democrats who support it. So the sentiment is correct, to a certain degree.
Nixon was the first to whom which the phrase "War on Drugs" was used, but it had been going on for many decades previously and had ... heated up quite a bit, certainly in terms of consumption and press about that, in the period of the cultural '60s prior to his assuming office in 1969. You might say "LSD Madness" was a major meme back then, and heroin was the big evil hard drug that caused the most fear.
This is largely from direct observation back then, e.g. in 3rd grade a bit before "War on Drugs" was coined I had to write a thorough workbook detailing all the major drugs being abused then, why they were bad for you, etc.
And, errr, here you posit "total - non-trivial number < most" (if I'm not too tired to express that); on its face it's just an impression you have. Very possibly a correct one, but then again you admit there are anti-War on Drugs Republicans. And in theory one of them could do a Nixon in China ... but we all know how a lot of Democrats would reply, no matter what their personal preferences were.
> And, errr, here you posit "total - non-trivial number < most"
I would posit that you have a significantly higher percentage of pro-legalization Democrats than Republicans. Most opposition to legalization comes from Republicans.
