Lawyer email marketing sits inside rules that ordinary marketers never think about. Many state bars treat a mass email to the public as attorney advertising, and some expect a label such as advertising material in the subject line or body, a named responsible attorney or a physical address for the firm. Claims about results, specialization or past verdicts are restricted in most states. Your specialist drafts with those rules in mind, flags anything that needs a partner's review and leaves the final judgment to the firm, since compliance is your call, not ours.
Targeted solicitation is a separate issue. Writing to someone known to need help with a specific matter, such as a recent accident, can trigger stricter solicitation rules than a general newsletter. For that reason, lists built from public records or purchased data are off the table, and every contact on the list should have a real relationship with the firm or a clear opt in.
Then there is the technical side. Marketing mail goes out from a dedicated subdomain with SPF, DKIM and DMARC aligned, so a spike in complaints never touches the domain your attorneys use for client correspondence. Google and other inbox providers now expect easy unsubscribe links and low complaint rates from bulk senders, and CAN-SPAM rules apply to every commercial message. Nothing confidential about a matter ever appears in a marketing email, and client files never flow into the email platform.