To what extent are US state laws enforceable across state lines?

Question

Can laws enacted by a state legislature be enforced on people or organizations that are not strictly within that state?

A notable example is Texas' S.B. 8 bill which essentially criminalizes anyone who aids in an abortion by providing funding, transportation, etc. If an individual or organization located in another state provides such funding, or in the case of a doctor located in another state provides an abortion, can a lawsuit be brought against them within the Texas state legal system?

Another example might be with regards to labor laws. If a state has a law, say, requiring a certain pay rate for overtime work, can a lawsuit be brought against an out-of-state employer for failure to comply with such policy (perhaps pertinent in the case of remote work or distributed work such as rideshare drivers).

Answer 1

To the extent Constitutionally permitted or as further limited by the state’s own law

Constitutionality, a suit may be brought (or a prosecution launched) when the state has personal jurisdiction over the defendant.

… a state court may only exert personal jurisdiction over an individual or entity with "sufficient minimal contacts" with the forum state such that the particular suit "does not offend 'traditional notions of fair play and justice.'"

What constitutes sufficient "minimum contacts" has been delineated in numerous cases which followed the International Shoe decision. For example, in Hanson v. Denckla, the Court proclaimed the "unilateral activity of those who claim some relationship with a nonresident cannot satisfy the requirement of contact with the forum State. The application of that rule will vary with the nature and quality of the defendant's activity, but it is essential in each case that there be some act by which the defendant purposefully avails itself of the privilege of conducting activities within the forum State, thus invoking the benefits and protection of its laws."

For the abortion bill, an organisation that provides funding to Texas residents probably has “minimum contacts”, an out-of-state doctor who treats all-comers probably doesn’t.

For employment laws: if the employee is based and work takes place in the state, yes.

There is a separate question of which state's law applies which is independent of which state's courts can hear the case. A California court can decide that it can hear a case according to Texas law for example although, in practice, if the California court felt that all of the issues were Texan, they would probably decide they lacked jurisdiction.