In December 1985, Kansas filed a complaint against Colorado before the Supreme Court over what it viewed as unfair diversion of water from the Arkansas River. Colorado denied the charges and made some allegations of its own against Kansas, continuing a feud between the two states over the river that dates back to 1902.

Today -- 23 years after the latest case was filed -- the attorneys general of both states will argue before the Supreme Court in what is likely the final chapter of the dispute. It is the first time in recent memory that two state attorneys general will argue against each other before the Supreme Court.

But missing in the courtroom will be Arthur Littleworth, who has been the Court's special master in the case since 1987. A leading water law expert in the California firm Best Best & Krieger Littleworth had a stroke earlier this year and can't attend. "My recovery is slow but steady," the 85-year-old Littleworth tells Legal Times in an e-mail.

"We'll miss him," says John Draper of Montgomery & Andrews in Santa Fe, N.M., who has represented Kansas in the litigation. "Even when we didn't agree with his results, all the parties have been very impressed with him."

In disputes like Kansas v. Colorado, which come under its so-called original jurisdiction, the Supreme Court is the tribunal of first, not last resort, which means it arrives without a lower court record. As a result, the Court appoints a special master to conduct the fact-finding and recommend a resolution.

There were evidently a lot of facts to find in this case. From 1990 to 2003, Littleworth held 270 days of trial at the 9th Circuit courthouse in Pasadena, amassing 2,900 records. Much of the evidence was hydrologic data aimed at determining to what extent Colorado had failed to limit irrigation wells along the Arkansas River in Colorado. As the Court described it earlier in the case, computer models were devised to "account for almost every Arkansas-River-connected drop of water that arrives in, stays in, or leaves Colorado."

As a result of that assessment in 2003, Colorado paid Kansas $34 million in damages, which Littleworth says in his report was "the first time that money damages have been tried and awarded in a case of this kind."

The issue before the Court today is the additional amount Colorado owes Kansas for expert witness fees, since Kansas was the prevailing party. Kansas puts the bill at $9.2 million, but Colorado cites a federal law capping expert fees at $40 per day -- which would lower the expert witness price tag to $163,000. Littleworth agrees with the $40 cap, and the high court will consider Kansas' objection to that judgment.

Littleworth's soft spot for frugality extends to his own service as special master. His fee -- paid jointly by the states -- was $250 an hour from 1987 to 2005, when it went up to $350, even though he could charge much more.

"Art always had a strong commitment to public service," says Eric Garner, the managing partner of Littleworth's firm, who counts Littleworth as his mentor. Did he expect his stint to last this long? "Water cases never really end," says Garner. "The case has meant a lot to him and to the firm. It has really been a crowning achievement of his career."