If you're watching the Democratic National Convention on either MSNBC or CNN, there's a good chance you'll catch of glimpse of Richard Nixon. Why? He's featured in a new ad for Amendment 64, the Regulate Marijuana Like Alcohol Act -- and like the campaign's first commercial, released in May, it takes a soft-sell approach to the issue. See both spots below.

"Our goal is not to attack anyone with this ad," says Betty Aldworth, who's both a spokeswoman for Amendment 64 and the narrator of the new clip, "but rather to encourage voters to think differently about marijuana and marijuana users." She adds her hope that the commercial will stand out because of its contrast to the negative political advertising currently dominating the airwaves.

The first images in the commercial are of Barack Obama hoisting brewskis -- photos juxtaposed with Aldworth-delivered reassurances that "we're not looking to end beer summits at the White House -- or change the way people behave on the campaign trail."

That's followed by a dissolve to a couple cuddling on a sofa and the line, "We just believe adults, in the privacy of their homes, should be allowed to use marijuana instead of alcohol if that's what they prefer."

Then comes Nixon and the statement that "forty years ago, our government launched a war on marijuana unrelated to the actual and limited harms of the substance." Finally, graphics accompany the conclusion that "it's time for a more sensible approach. It's time to regulate marijuana."

This pitch is more on-the-nose than the one at the heart of the May commercial, in which a young woman is seen explaining to her mother via e-mail why her experiences with drinking in college have convinced her to shift to marijuana.

The goal this time around is to "highlight the disconnect between how we treat marijuana and alcohol users in society," Aldowrth says. "Hopefully, it will encourage people to question why we use alcohol so publicly as a way to connect to voters, but it's a crime for adults to use marijuana, which is an objectively less harmful substance than alcohol."

As for the Nixon nod, Aldworth says, "It was under Nixon's administration that many of our current punitive marijuana policies were developed, and where the option to treat marijuana differently was presented and ignored. So it's trying to remind voters that our current marijuana policy is not based on science or social reality. It's based on misconceptions about marijuana and marijuana users."

Does Smart Colorado, the No on 64 campaign, see it that way? Not exactly.

Continue to get the No on 64 response to the commercial, plus both Yes on 64 ads and new polling data about the amendment. In a statement about the new commercial, No on 64 campaign director Roger Sherman criticizes the spot for not addressing the potential negative impact marijuana can have on children.

"There is an increasing body of evidence about the detrimental effects of marijuana on the developing brain," says Sherman in reference to Duke University study suggesting that adolescent pot use can cause long-term IQ drops. "The out-of-state proponents of legalizing marijuana are understandably concerned about voters hearing the truth about the dangerous consequence to kids here in Colorado should Amendment 64 pass."

Of course, Amendment 64 proponents have repeatedly emphasized that the initiative would make small amounts of recreational marijuana legal only for adults age 21 and over. They've also stressed that they want to restrict access to pot for anyone younger and believe regulation will be more effective in doing so than the current system.

The Smart Colorado release that accompanies Sherman's assertion above contends that "polls continue to show the effort to amend the Colorado Constitution to legalize recreational marijuana is failing with voters," but that's not quite right. Rather, the latest survey by Public Policy Polling, on view below, suggests that momentum has stalled. According to PPP, 47 percent of respondents favor Amendment 64, while 38 percent oppose it -- numbers identical to those the service collected last month.

The new ad is intended to improve these figures in a manner that's non-confrontational. "We want people to recognize that policies treating marijuana and alcohol users differently don't make sense today," Aldworth notes. "As the ad says, it's time for a more sensible approach -- and we believe a more sensible approach is regulating marijuana like alcohol."

Below, see the new ad, followed by the May commercial and information about the Public Policy Polling survey.

More from our Marijuana archive: "Video: Amendment 64's first campaign ad encourages marijuana talks."