Is this an exercise of the US Supreme Court’s original jurisdiction?
<p>I was checking the US Supreme Court’s website for recent opinions and came across one for <a href="https://www.supremecourt.gov/opinions/17pdf/137orig_new_2cp3.pdf" rel="nofollow noreferrer">State of Montana v. State of Wyoming and State of North Dakota</a>. This opinion looks very different than the others I’ve read in the past. Specifically:</p>

<ul>
<li><p>The case was based on a “Bill of Complaint,” not a writ of certiorari, which is what I’m more used to seeing.</p></li>
<li><p>The case references a “Special Master,” a term I’ve never seen before.</p></li>
<li><p>The opinion is not signed, not even “Per Curiam.”</p></li>
<li><p>The opinion states a “Decree,” which is quite different than the structure I’m used to seeing.</p></li>
<li><p>The case number is “137, Orig.,” which seems to be a different numbering system than what’s typically used.</p></li>
</ul>

<p>I’ve been trying to Google these terms to see what they mean, but I’m having trouble finding anything on them.</p>

<p>I know that the US Supreme Court has original jurisdiction in cases between states. Is this an exercise of that jurisdiction? If not, what exactly is this type of opinion?</p>

<p>Yes. States, when litigating among one another, file bills of complaint such as the one you linked to in your question. </p>

<p>A <a href="https://www.mediate.com/articles/kellerC.cfm" rel="nofollow noreferrer">special master</a> is usually a court appointee whose job it is to assist with making sure the judgment is carried out properly. This could take the form in appointing a special master to take over a police department's operations in the wake of civil rights rulings against it for corruption, racism, etc. Another example is they can be sent to make evidentiary rulings at a deposition on the spot. </p>

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