Quasi in rem (Latin, "as if against a thing") is a legal term referring to a court action based on the property rights of a person absent from the jurisdiction.
In the American legal system the state can assert power over an individual simply based on the fact that the individual has property (e.g., a bank account, debt, shares of stock, real property) within the state. A quasi in rem action is commonly used when jurisdiction over the defendant is unobtainable due to his/her absence from the state. Any judgment will affect only the property seized, as there is no in personam jurisdiction.
Judgment based on quasi in rem jurisdiction generally affects rights to the property only between the persons involved in the legal action, and does not "bind the entire world" as does a judgment based on in rem jurisdiction. The claim does not have to be related to the property seized, but the person must have minimum contacts with the forum state in order for jurisdiction to be proper.
On June 24, 1977, the U.S. Supreme Court decided that the requirement that the circumstances giving rise to jurisdiction comply with the notion of "fair play and substantial justice" should apply to quasi in rem jurisdiction cases as well. This decision significantly diminished the utility of quasi in rem jurisdiction because if the case meets the minimum contacts and fair play and substantial justice tests, the action can be brought under in personam jurisdiction.
Quasi in rem jurisdiction, however, can still be an effective option in bringing a lawsuit in a particular court since quasi in rem jurisdiction can overcome the limitations of the long-arm statute of a particular state.