With Gov. Charlie Baker's stay at home advisory now in place, there are now a number of questions about the legal implications of the emergency order. WGBH Morning Edition host Joe Mathieu spoke with Northeastern University law professor and WGBH News legal analyst Daniel Medwed on Tuesday to learn more about how officials plan to craft and enforce the advisory. The transcript below has been edited for clarity.

Mathieu: Yesterday, the governor issued an executive order demanding, as we've been reporting, non-essential businesses close their doors today at noon. It will last until the 7th of April. First of all, Daniel, what is the legal basis for issuing such an order?

Medwed: The legal authority comes from the governor's power to declare a state of emergency in the event of an imminent natural or man-made disaster pursuant to what's known as the Civil Defense Act. It was passed back in 1950 at a time when we were concerned about escalating tensions with the Soviet Union. And looking at that act is like a window into our past. There are references to fallout shelters [and] to requisitioning private property for public use. Governor Baker has invoked this act before, most notably in 2018 after the Merrimack Valley gas explosion in Lawrence, and he's also relied on it in issuing more than a dozen executive orders since March 10th. The latest of which, of course, was yesterday's order, which contained, among other things, an advisory from the Department of Public Health urging residents to stay at home and to practice social distancing.

Mathieu: What about, Daniel, the ability of cities and states to craft their own rules? What powers do they have?

Medwed: They have broad powers to enact protective measures as well. In fact, Nantucket issued a shelter in place order on Sunday night. I believe it went into effect yesterday. But notably, a statewide order supersedes any and all local ordinance that might interfere or impede with the statewide missive. So yesterday's order essentially takes precedence over any municipality's ordinance.

Mathieu: You're mentioning that order yesterday that takes effect today, Daniel, included an advisory from the Department of Public Health urging people to stay at home. That is different from a shelter in place order. How?

Medwed: Well, here's the key difference. The order urges residents to "limit activities outside of the home and to practice social distancing," but it did it does not formally require people to shelter in their homes. People may still go to the grocery store, to the pharmacy, grab some fresh air [and] exercise. We're not yet in a place where the governor deems it necessary for us to remain in our homes at all times. Gatherings, however, are now limited to no more than 10 people. And as you noted before, the governor has demanded that businesses deemed non-essential must close by noon today.

Mathieu: And Daniel, we can still go outside, right? The order does address public spaces like parks.

Medwed: Yes. On the one hand, the order makes clear that it does not prohibit gatherings of more than 10 people in an unenclosed outdoor space like a park. So if you show up to your local park and there are already 10 people there, you don't have to go back home. But on the other hand, the order does explicitly ban athletic and recreational pursuits that might bring people into close physical contact, notably even if it involves fewer than 10 people and regardless of where they occur. So no pickup street hockey or basketball or flag football, anything like that.

Mathieu: We only have 30 seconds, Daniel. But what about enforcement? Is it a crime to violate the terms of this order?

Medwed: Yes. Here's how the enforcement works. You could either get a civil fine of up to $300 per violation or potentially a criminal penalty under Section 8 of that Civil Defense Act I referenced, which provides for a criminal fine of up to $500 and/or imprisonment potentially for up to a year. Now, I imagine the police have bigger things on their plate than enforcing residents all the time, so really I think it's up to community norms and social responsibility more than the police to serve as a mechanism for enforcement here.