While lawmakers regularly travel to educate themselves about issues of public import, the context for the Colorado trip makes it unusual: Beacon Hill leaders have made clear there is not the political interest or will to pass a legalization bill, but they have floated the idea of tinkering with a legalization law, if it garners sufficient signatures to make the statewide ballot and if voters approve it.

They’re poised to see a cultivation facility, tour a marijuana dispensary, and pepper top state, municipal, and law-enforcement officials with questions about the implementation of the voter-approved law. The four-day trip is being arranged and paid for by the New York-based Milbank Memorial Fund, which describes itself as a nonpartisan health policy foundation.

DENVER — Eight state senators are flying into Colorado this week for a primer on life in a state that has already legalized marijuana, in case Massachusetts voters follow suit this November and lawmakers have to decide quickly how to respond.

Senator Jason M. Lewis, chairman of the special Senate committee on marijuana and leader of the trip, said if voters greenlight the proposal, the Legislature might want to pass laws to address issues the referendum doesn’t substantively address — such as drugged driving — and might also want to change the law itself.


“There may also be particular provisions in the ballot question where lawmakers have concerns,” he said, “and may want to at least debate a different approach.”

“What we’re contemplating here is a major change in social policy for Massachusetts,” Lewis, a Winchester Democrat, said, ticking through ramifications on public health, public safety, and the creation of a new industry. But, he said, he wouldn’t characterize any adjustments lawmakers might make as undoing the will of the voters, but rather focused on “the details” of how the state moves forward with legalization.


In 2012, voters approved the use of marijuana for medical purposes, but the state’s rollout of that law was disastrous and a dispensary did not actually open for patients until June 2015. Lewis said it’s important to gather as much information as possible for lawmakers and regulators in hopes that, should marijuana be legalized for recreational use, the implementation will be smoother.

While a bill to legalize marijuana was put forward by lawmakers who say they would prefer a deliberative process rather than a referendum vote, it is unlikely to go anywhere in the House or Senate.

House Speaker Robert A. DeLeo and Governor Charlie Baker both oppose the legalization of marijuana. Senate President Stanley C. Rosenberg has not publicly endorsed or opposed legalization.

But the speaker has floated the prospect of adjusting the law, should it pass.

“If there were some problems [with] the way it was written, I wouldn’t hesitate, probably, to have the Legislature take a second look and make any necessary changes that we felt had to be made,” DeLeo said in March.

While lawmakers are often reticent to adjust or undo a law passed by a popular vote, there are precedents.

In 2000, voters passed a ballot initiative knocking the state income tax rate down from 5.85 percent to 5 percent in steps. The first ticks downward took place at the beginning of 2001 and 2002. But then the Legislature, facing difficult economic times, froze the final tax cut and set up a much slower diminution — so slow, in fact, the tax rate still hasn’t reached 5 percent. It’s 5.1 percent as of Jan. 1.


Analysts say there is an inherent tension in adjusting ballot questions.

Jeffrey M. Berry, a Tufts University political science professor, said “legislators have to be very careful to not appear to overturn the will of the people.” So if they pass legislation changing a ballot measure, “it really needs to appear to be fine-tuning existing law rather than overriding the policy.”

Still, Berry said lawmakers taking a trip to Colorado is a “good idea.” Just as businesses seek best practices from other companies, he argued, so too should lawmakers look to other states for ways make the best public policy.

Legalization advocates in Massachusetts have met the first and most arduous signature-gathering hurdle and are expected to clear the other obstacles to putting a measure on the ballot in November that would legalize recreational marijuana use for those 21 and older.

The proposed law from the Campaign to Regulate Marijuana Like Alcohol in Massachusetts would create a new “Cannabis Control Commission,” with members appointed by the state treasurer to oversee a system of marijuana stores, grow facilities, and manufacturers of edible products like brownies.

The measure would impose a 3.75 percent excise tax on retail marijuana sales, in addition to the state’s 6.25 percent sales tax — and it would also allow cities and towns to levy an additional 2 percent tax that the municipalities could keep. It would also allow adults to grow up to six marijuana plants in their home, would give a leg up to medical marijuana dispensaries that want to become retail stores, and set a January 2018 time frame for when retail sales could commence.


A spokesman for the legalization campaign, Jim Borghesani, said his group is “very pleased” that legislators are headed to Colorado to find the facts on the ground. He said the rollout in Colorado, one of four states and the District of Columbia where voters have decided to legalize marijuana, has, for the most part, been successful.

Borghesani said the campaign anticipates that any changes legislators might make to a successful ballot measure would be “modest and nondramatic.”

But, he warned, “If they reverse the will of the voters, it would be damaging.”

According to the committee, the lawmakers set to participate in the trip are Lewis; John F. Keenan, a Quincy Democrat; Linda Dorcena Forry, Democrat of Dorchester; Richard J. Ross, a Wrentham Republican; James T. Welch, a West Springfield Democrat; Michael O. Moore, a Millbury Democrat; Viriato M. deMacedo, a Plymouth Republican; and Michael J. Rodrigues, a Westport Democrat.

Judith Zimmer, a spokeswoman for the Milbank Memorial Fund, which is paying for travel, hotel accommodations, and meals, said the fund usually doesn’t know the cost of a trip until it’s over.

But, she said, “In Colorado, four nights at the hotel will come to $580 per person. Airfares range from $300 to $700.”


In a statement, Christopher F. Koller, president of the fund, said the nonprofit and its board have no involvement for or against legalization but rather are committed to strengthening “the ability of state leaders to make good health policy.”

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Joshua Miller can be reached at joshua.miller@globe.com. Follow him on Twitter @jm_bos. Click here to subscribe to his weekday e-mail update on politics.