That is the question on the minds of libraries vs. publishers. Publishers and the American Association of Publishers believe the new law, which compels publishers to license e-books and digital audiobooks “on reasonable terms that would enable public libraries to provide library users with access to the electronic literary product," violates the US Copyright Act. The AAP claims that the Copyright Act governs distributing creative works of authorship, and no state can mandate compulsory licenses for print or digital books. Moreover, the AAP argues that Maryland libraries don't have the authority to solicit or engage in collective pricing negotiations.
The Maryland Library Association, however, has moved forward with a position statement on just what they believe the Maryland legislature meant by "reasonable terms (given that the law has not been litigated yet). The MLA says, among other things, that "'reasonable terms' could include a limitation on the number of times a library could lend a digital copy, based on the number of times a library typically could lend a copy of a work in a physical format before replacing it due to damage or deterioration." You can read the entire position paper here: https://www.mdlib.org/files/docs/press/statement.pdf
Given the potential impact this has on libraries (being that Maryland, as well as New York, have passed digital content laws), Perry Law will continue to provide any updates.