“Project SAM was created because we were concerned about the mad rush to legalization in this country and the false dichotomy presented as policy,” Mr. Kennedy said. “Incarceration or legalization. Lock ‘em up or let ‘em use. This is not where we want this debate to devolve to. … We need a more enlightened, thorough and thoughtful discussion and policy debate.”

Immediately beforehand, Mason Tvert, Colorado’s best-known legalization advocate, held a news conference outside the Denver Press Club where he accused Mr. Kennedy of hypocrisy for lecturing the public on marijuana even though the Kennedy empire was built on liquor.

“Why is it that someone who is an heir to an alcohol fortune would want to keep an alternative to alcohol that’s less harmful illegal?” said Mr. Tvert, who ran the successful Amendment 64 campaign. “This is an effort to keep marijuana illegal when the public is overwhelmingly stating to recognize that it doesn’t work.”