What can law students (or a lay person) not do, if they haven't passed the state bar/bar exam or finished a law degree?
Is the bar exam like a certification program in engineering? Or is there more to it?
Passing the bar exam allows one to get a license to practice law. It is to some extent like a certification exam. It is in all US states a crime to practice law without a license. Exactly how "practice law" is defined varies a bit, but holding yourself out as a lawyer, opening a law office, or taking money for representing people in court is petty much always included. Other related things are often included also. Even if one has passed law school and thus earned a law degree, it is a crime to practice law without a license, and one cannot obtain a license without passing the bar exam.
In some states it is possible, but hard, to pass the bar without a law degree, in some a degree is required.
so the main thing a law student cannot (legally) do that one who has passed the bar exam can is practice law.
I found this definition of the practice of law on an official Maryland web page:
The “practice of law” is defined in the Maryland Code as follows:
(1) “Practice law” means to engage in any of the following activities:
(1) (i) giving legal advice;
(1) (ii) representing another person before a unit of the state > (1) > > > (1) (iii) performing any other service that the Court of Appeals defines as practicing law.
(2) “Practice law” includes:
(2) (i) advising in the administration of probate of estates of decedents in an orphans court of the state;
(2) (ii) preparing an instrument that affects title to real estate;
(2) (iii) preparing or helping in the preparation of any form or document that is filed in a court or affects a case that is or may be filed in a court; or
(2) (iv) giving advice about a case that is or may be filed in a court
Md. Code Ann. Bus. Occ. & Prof. § 10-101(h).
The Court of Appeals has interpreted the practice of law to include “utilizing legal education, training, and experience [to apply] the special analysis of the profession to a client’s problem.” Kennedy v. Bar Ass’n of Montgomery County, Inc., 316 Md. 646, 662 (1989). In addition, meeting with potential clients may constitute the practice of law. Id. at 666. The practice of law is “ ‘a term of art connoting much more than merely working with legally related matters.’” Attorney Grievance Commission v. Shaw, 354 Md. 636, 649 (1999) (citations omitted). “ ‘Functionally, the practice of law relates to the rendition of services for others that call for the professional judgment of a lawyer.” Id. Therefore, the Court of Appeals ruled that a bar applicant who had served as a hearing examiner for the Maryland Department of Employment & Training was not engaged in the practice of law, and therefore not eligible to take the attorney’s examination. In re Application of Mark W., 303 Md. 1, 4-6 (1985). “The hallmark of the practicing lawyer is responsibility to clients regarding their affairs, whether as advisor, advocate, negotiator, as intermediary between clients, or as evaluator by examining a client’s legal affairs.” In re Application of R.G.S., 312 Md. 626, 632 (1988).
Also relevant is RULE 19-305.5. UNAUTHORIZED PRACTICE OF LAW;
Some comment mentioned assistance in pro bono work by law students. I found Maryland Rule of Professional Conduct 19-220 - Legal Assistance by Law Students which provides in pertinant part, omitting the definitions of terms:
(b) Eligibility. A law student enrolled in a clinical program or externship is eligible to engage in the practice of law as provided in this Rule if the student:
(b) (1) is enrolled in a law school;
(b) (2) has read and is familiar with the Maryland Attorneys' Rules of Professional Conduct and the relevant Maryland Rules of Procedure; and
(b) (3) has been certified in accordance with section (c) of this Rule.
(c) ... The certification shall state that the student is in good academic standing and has successfully completed legal studies in the law school amounting to the equivalent of at least one-third of the total credit hours required to complete the law school program. ...
(d) Practice. In connection with a clinical program or externship, a law student for whom a certification is in effect may appear in any trial court or the Court of Special Appeals, or before any administrative agency, and may otherwise engage in the practice of law in Maryland, provided that the supervising attorney (1) is satisfied that the student is competent to perform the duties assigned, (2) assumes responsibility for the quality of the student's work, (3) directs and assists the student to the extent necessary, in the supervising attorney's professional judgment, to ensure that the student's participation is effective on behalf of the client the student represents, and (4) accompanies the student when the student appears in court or before an administrative agency. The law student shall neither ask for nor receive personal compensation of any kind for service rendered under this Rule, but may receive academic credit pursuant to the clinical program or externship.
This page about the Univeristy of Maryland School of Law's public Servie program describes the program as: "one of the region’s largest public interest law firms" and states:
Working alongside faculty, students provide 75,000 hours of free legal service annually to Maryland citizens in need[.]
This is obviously a widely recognized and approved activity.
If you have not taken or passed the Bar, you are not a lawyer. You could have a doctorate degree in law, but you would not be a lawyer. And without having passed the Bar, you are not legally allowed to practice law.
So in other words: the law student is in the same shoes as a paralegal in most states. They may know about the law more than a normal person, but they may do nothing more than a normal person. This means they can not give legal advice and can not represent people other than themselves as a pro se litigant. Yes, without the bar exam and license to be a lawyer, they are just a normal person in the eyes of the courts. They might assist a lawyer more effectively than a total layman when researching for a case - but that is not practicing law.
There's an exception to that: Only when the lawyer-to-be takes part in specific training under the supervision of accredited lawyers, then they can be treated as a temporary lawyer for that case. Typically such happens in a law clinic or similar project.