Paul Callan is a CNN legal analyst, a former NYC homicide prosecutor and currently is "of counsel" to the New York law firm of Edelman and Edelman, PC, focusing on wrongful conviction and civil rights cases. Follow him @paulcallan . Danny Cevallos ( @CevallosLaw ) is a CNN Legal Analyst and a personal injury and criminal defense attorney practicing in Pennsylvania and the U.S. Virgin Islands. Callan and Cevallos occasionally work together on civil rights projects at Edelman & Edelman. The opinions expressed in this commentary are theirs.

(CNN) One of the many decisions facing President Donald Trump is whether to continue the federal government's hands off policy on marijuana, which has allowed the legal sale of the substance in 27 states.

Sen. Jeff Sessions, Trump's nominee for attorney general, has signaled that the new administration could end the practice of allowing states to legalize pot, telling a congressional hearing on his nomination: "It's not so much the attorney general's job to decide what laws to enforce. We should do our job and enforce laws as effectively as we're able."

CNN Opinion asked Paul Callan and Danny Cevallos, two of the network's legal analysts, for their views on the issue:

1. Marijuana is illegal under federal law. It is a Schedule 1 controlled substance, making possession and distribution of the drug a federal felony. Unless and until the law is repealed, doesn't the President have an obligation to enforce the law as written?

Yes. As a criminal defense attorney you might think I'd be anti-enforcement instead of pro-enforcement. But there's no question that the President and the Attorney General are charged with enforcing the law. Arbitrary or selective enforcement of existing law is itself an abuse of power. The Equal Protection Clause already prohibits the " selective enforcemen t" of a law based on standards like race or religion. The broad discretion of the executive branch or a prosecutor to charge identical defendants with different crimes creates a real threat of unequal, and unconstitutional, treatment. If you want to legalize marijuana, the solution for the federal government is not to be willfully blind to existing federal law. That sends a bad message. The solution is to be proactive: get rid of the outdated federal law.

Paul Callan: No. Sure, Danny is correct that the President and the Attorney General are supposed to enforce the laws as written, but there is also an important concept called prosecutorial discretion. The government has limited resources and can choose to focus on terrorists, kidnappers, murderers and big-time white collar criminals rather than pot smokers listening to Daft Punk's latest rendition of "Human After All." ( No. Sure, Danny is correct that the President and the Attorney General are supposed to enforce the laws as written, but there is also an important concept called prosecutorial discretion. The government has limited resources and can choose to focus on terrorists, kidnappers, murderers and big-time white collar criminals rather than pot smokers listening to Daft Punk's latest rendition of "Human After All." ( Check it out, Danny. )

The statute books are filled with laws that are not being enforced because they are obsolete and legislators haven't gotten around to repealing them. There are an abundance of such laws listed in numerous internet sites.

(Peruse this lis t at your own risk as some of these laws have now changed)

But more serious examples are closer at hand. For example, in 2013 the Justice Department issued a memo from Deputy Attorney General James Cole outlining a limited enforcement policy of only prosecuting federal marijuana criminal violations in cases of violence, interstate smuggling, distribution to minors and in matters of adverse impact on public health. Attorney General nominee Sessions would be wise to follow the Obama approach here, and President Trump should understand that there are a lot of electoral votes in those weed-legal states.

And as for my friend Danny Cevallos...it is time for him to face reality and, as they say in Colorado: "Chill".

2. President Obama in his final months in office has pardoned thousands of drug offenders serving heavy time in federal prison for the possession and sale of the drug. Should President Trump continue with the Obama pardon policy given the number of states which have now legalized marijuana?

Callan: Yes. President Trump would be wise to follow the example of his predecessor by making use of the pardon and commutation power -- with care and discretion. The prisons are filled with inmates who have been sentenced to lengthy prison sentences for drug-related crimes. Many have gotten old in prison and no longer pose a threat to society. Many were Yes. President Trump would be wise to follow the example of his predecessor by making use of the pardon and commutation power -- with care and discretion. The prisons are filled with inmates who have been sentenced to lengthy prison sentences for drug-related crimes. Many have gotten old in prison and no longer pose a threat to society. Many were unjustly convicted ; we have seen a massive increase in costly wrongful conviction lawsuits throughout the nation.

Members of America's minority communities have been aggrieved by what they perceive as the mass incarceration of their young men due to unjust drug laws that are no longer relevant in modern America. The pardons and commutations should be carefully monitored to make sure violent criminals are not slipping through the cracks but President Trump should follow President Obama's example in continuing this policy.

Cevallos: No. Does anyone else think it's a huge waste of resources for President Obama to pardon federal drug offenders instead of getting rid of the federal law that made many of them federal drug offenders in the first place? Think of the resources frittered away: existing federal law is what causes investigations, arrests, trials, appeals, and incarceration. Then, ultimately the same branch of government that spent all that time and money convicting the person grants a pardon or commutation -- effectively canceling out all those resources spent getting the conviction.

Wouldn't it be a lot less expensive to get rid of the federal law that led to the expensive investigation, arrest, trial, appeal, and incarceration in the first place? President Obama's pardon policy for drug offenders is a good thing, but it's largely cosmetic, and it only conceals the bruises that the federal government itself continues to inflict upon the citizenry. Paul Callan wants to paint himself as a freedom fighter here, and he's right that the pardon power is good for freeing those for acts no longer considered crimes. But true freedom isn't pardoning the crime after the person has been incarcerated. It's getting rid of the crime itself.

3. The doctrine of federalism has traditionally been supported by Republicans. Should President Trump's Republican Administration allow the states to experiment with marijuana legalization under the doctrine of federalism.

Cevallos: No. As Supreme Court Justice Louis Brandeis : No. As Supreme Court Justice Louis Brandeis put it : "it is one of the happy incidents of the federal system that a single courageous State may, if its citizens choose, serve as a laboratory; and try novel social and economic experiments without risk to the rest of the country." I agree completely with that general sentiment. But marijuana is different.

States legalizing pot is "experimentation" with something that is flat-out illegal under federal law. When the threat of federal prosecution hangs over a marijuana shop owner or user, states cannot truly serve as laboratories. It's hard to experiment when banks, investors, insurance companies, and even attorneys are reluctant to provide necessary services, for fear of federal criminal penalties or professional discipline.

Paul Callan may cheer states for their open flouting of federal law, but would he represent a shop owner if he thought the bar association's disciplinary committee would come after him? Heck no. He's as afraid of the ethics board as I am. And so are plenty of other lawyers , who fear potential disciplinary action for counseling a client to engage in the business of violating federal law. Everyone loves the idea of civil disobedience...until it's their turn to actually get hit with the fire hose or the police truncheon.

Callan: Yes. There is a lot of truth in a statement often heard in conservative gatherings: "The states created the federal government and not the other way around..." The Constitution was drafted by founding fathers deeply sensitive to the concept of a limited federal government with a vibrant democracy flourishing at the local level. Nowhere is the leadership of the states more clearly demonstrated than in the approval of recreational and medical marijuana in Yes. There is a lot of truth in a statement often heard in conservative gatherings: "The states created the federal government and not the other way around..." The Constitution was drafted by founding fathers deeply sensitive to the concept of a limited federal government with a vibrant democracy flourishing at the local level. Nowhere is the leadership of the states more clearly demonstrated than in the approval of recreational and medical marijuana in 27 states at last count.

This state laboratory creates a superb opportunity to test different approaches to legalization rather than rely on the alleged wisdom of Cevallos' elite pals in DC, many of whom have just been unceremoniously kicked out of office in the tumultuous election of 2016.

Follow CNN Opinion Join us on Twitter and Facebook

Local authorities will ensure that rather than a "one size fits all" federal approach, the best state ideas will be imitated and implemented by other states. And as for the Cevallos claim that lawyers will never represent weed store owners for fear of an ethics prosecution, the Colorado Supreme Court has just given the weed lawyers the green light to represent marijuana businesses. Perhaps Danny Cevallos should consider opening a Denver office.

4. Should marijuana be legalized because taxing it will lead to a rich source of government revenue?

Cevallos: No. Don't get me wrong. I think ending federal marijuana prohibition is a good idea. I also hope that taxing the drug will be a good source of revenue for states and the federal government. Paul Callan knows that this is a popular argument. But when you think about it, taxing vices hasn't always been the cure for all ills.

Gambling has been legal and taxed for years in places like Atlantic City, where it is the town's primary industry. Has anyone strolled down that town's main drag lately? It's hardly a monument to American prosperity. Speaking of gambling, how about the lottery ? State-sponsored gambling is heavily taxed and supposedly goes to help senior citizens and schools. But, would Paul Callan honestly say that the net effect of the lottery on society has been a good one? Hopefully marijuana taxation will be different. Early reports are positive: marijuana generates a lot of tax revenue in the legalized states. But there's good reason to remain skeptical.

Callan: Yes, Danny raises a legitimate point that taxing vices often fails to raise the large amounts of revenue promised. Things like the lottery seem to generate more money for state bureaucracies than for education. Although Atlantic City looks grim, the Yes, Danny raises a legitimate point that taxing vices often fails to raise the large amounts of revenue promised. Things like the lottery seem to generate more money for state bureaucracies than for education. Although Atlantic City looks grim, the gambling vice tax is thriving in Las Vegas, Indian Reservations around the country and even in Bethlehem, PA in Danny's home state. The lesson is that you must carefully pick the vice you seek to tax. Given the track record to date marijuana seems a winner on the tax revenue side. In Colorado and Oregon, recreational use has spawned a $7.1 billion tax-generating industry.

And for vice comparison purposes, the taxing of alcohol has proven to be quite lucrative to the states. Alcohol taxes yielded over $9 billion in revenues in 2015 with projections of $10.18 billion by 2021. As a drug which is arguably far less dangerous, marijuana is likely to generate an even greater revenue stream. The states are finding it difficult to overlook such a revenue stream given the thriving underground economy where only illegal producers and dealers enjoy the profit. If Mr. Trump really does want to lower corporate and personal income taxes, legalized, taxed marijuana may be of assistance in achieving that goal.

5. Many assert that marijuana is no more dangerous than alcohol, yet it is illegal under the laws of many states and the federal government. Is it fair to treat the substances so differently under law?

Callan: No. Wisely, Cevallos will not even fight me on this one. Marijuana is far No. Wisely, Cevallos will not even fight me on this one. Marijuana is far less dangerous than alcohol and there is a great hypocrisy in permitting legal sales of the older generation's vice, alcohol, while locking up younger Americans who partake of the far less dangerous marijuana. Of course it must be conceded that the drug is not without serious risks, particularly for those with a propensity toward drug abuse. This is yet another reason to allow experimentation on a state level to see how legalization works out in the real world. As for the Cevallos argument that a teetotaling POTUS will resist legalization, there are more than a few reasons to suggest otherwise. He has previously indicated support for medical marijuana stating:

"In terms of marijuana and legalization, I think that should be a state issue, state-by-state...Marijuana is such a big thing. I think medical should happen -- right? Don't we agree? I think so. And then I really believe we should leave it up to the states." Washington Post, October 29, 2015

And let's face it, most liberals and progressives would have to be under the influence of drugs to support him, so there may be new Trump supporters if legalization succeeds. Though let's hope the new president maintains his teetotaling ways as heaven help us all if POTUS starts smoking "Trump Weed" before preparing his next 3 a.m. tweet.

Cevallos: No. Paul Callan has me here. Prohibiting marijuana and allowing alcohol makes zero sense. But then again, nothing about vice crimes is "fair" or even "logical". In fact, alcohol is much No. Paul Callan has me here. Prohibiting marijuana and allowing alcohol makes zero sense. But then again, nothing about vice crimes is "fair" or even "logical". In fact, alcohol is much more dangerous than marijuana. Not only is it bad for your body, it's a major contributor to accidents, and violence. But the real question is: could Mr. Callan convince Mr. President?

Our new POTUS is a self-described teetotaler, a nondrinker and non-drug user. And he's not the kind who stopped drinking because he used to have a problem, who hit a Bukowski-like bottom and turned his life around in AA. Trump is the kind who says he has never had a sip of alcohol in his life. Those people are intense. They usually like order and control. It's easy to imagine Trump might be intolerant of vices like marijuana. Then again, he's been socially liberal in many ways too. It's hard to predict where his administration will come down on the marijuana industry.